Research and analysis

Examination of the links between parental conflict and substance misuse and the impacts on children’s outcomes

Published 6 April 2021

Applies to England, Scotland and Wales

A report of research carried out by Cordis Bright on behalf of the Department for Work and Pensions.

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Executive Summary

This report is a literature review examining the links between parental conflict and substance misuse and the impacts on children’s outcomes. Three sections investigate:

1. The impact of parental conflict and substance misuse on children
2. Interventions for addressing parental substance misuse and conflict and their relative effectiveness
3. What characteristics of effective practice can be identified across interventions?

In addition, the review identifies where gaps exist in the evidence base and where these may need to be supplemented for the UK context.

Findings

Understanding the impact of parental conflict and substance misuse on children

The review finds that there is consistent evidence of an association between substance misuse and parental conflict. Some studies point to this association being causal. Most longitudinal studies support the view that substance misuse increases the incidence of parental conflict though there are other studies that highlight how parental conflict can lead to substance misuse. In all cases there is less evidence regarding the mechanism by which one leads to the other and how it interacts with other stressors. The relationship is likely to be complex.

The nature of the negative outcomes for children in families experiencing both substance misuse and parental conflict appears to be the same as for those in families experiencing either substance misuse or parental conflict alone, i.e. mainly externalising or internalising behaviours. There is, however, consistent evidence that children affected by both parental substance misuse and conflict are more at risk of presenting these behaviours. A number of other stressors (including housing, financial instability, crime, schooling or parental mental health) can act cumulatively to increase a child’s risk of negative outcomes.

Interventions addressing parental substance misuse and conflict and their relative effectiveness

The review identified few interventions explicitly aimed at tackling both substance misuse and parental conflict.

There is consistent evidence that behavioural couple’s therapy (BCT) results in a greater and longer-lasting reduction in substance use than individual behavioural therapy, and also improves relationship satisfaction and functioning in intact couples. There is also some evidence that BCT can improve outcomes for the couple’s children.

There is some evidence that the involvement of the whole family in substance misuse treatment can increase treatment engagement rates and lead to greater reductions in substance misuse than treatment delivered to the individual alone. There is more mixed evidence for the effectiveness of whole-family interventions on family functioning and there remains a lack of evidence regarding what form of family involvement is most effective.

The review identified that interventions often helped to develop the following set of skills in parents and children:

• helping parents to take responsibility for their actions and to understand the impact of their actions on their families
• improving communication between a couple and within the family as a whole
• skills training focused on emotional coping strategies, both to manage triggers to substance use and to improve parenting practices and conflict management

The development of these skills was shown by studies to help improve outcomes relating to substance use, parental conflict, parenting practices and child development simultaneously.

Characteristics of effective practice

While successful interventions take many forms, and there are no definitive rules for ‘what works’, this review highlighted a number of considerations and common themes relating to design and delivery which influence the effectiveness of interventions. Principal themes drawn out in this review were: timing and sequencing, engagement and retention, socio-demographic characteristics of the target group, intensity and length of intervention, format of intervention, techniques employed and multi-agency working.

Acknowledgements

This research was commissioned by the Department for Work and Pensions. The authors would like to thank Kate Warner and Ailsa Redhouse who have provided the key point of contact and support.

Author details

Caitlin Hogan-Lloyd is a Consultant at Cordis Bright

Colin Horswell is Managing Director and Senior Consultant at Cordis Bright

Suzie Langdon-Shreeve is a Consultant at Cordis Bright

Glossary of Terms

Term	Definition
Alcohol misuse	Alcohol use above low risk levels, leading to risk of both short- and long-term health and social problems.
Behavioural couples therapy (BCT)	A substance use intervention that seeks to directly address the pattern by which substance use and relationship problems can reinforce each other, by making use of the couple relationship as a tool to support the substance abusing partner in their effort to change, and to alter the family environment to one which better promotes abstinence.
Cognitive behavioural therapy (CBT)	A collection of therapeutic methods that provide people with mental strategies for managing their thoughts, moods, and feelings.
Co-morbidity	When two conditions or issues occur simultaneously or sequentially in the same individual, or within the same family.
Cross-sectional study	A study that involves observation or measurement of differentiated study groups at the same point or points in time. This is contrasted with a longitudinal study, which collects data from the same individuals at more than one point in time.
Dependence	The diagnostic threshold for dependence on a substance is three or more of the following occurring together at some point over the last year a strong desire to take the substance; difficulties in controlling its use; persisting in its use despite harmful consequences; a higher priority given to drug use than to other activities and obligations; increased tolerance; and sometimes a physical withdrawal state.
Domestic abuse (DA)	Any incident or patterns of incidents of controlling, coercive or threatening behaviour, violence or abuse between those aged 16 or over who are or have been intimate partners or family members, regardless of their gender or sexuality.
Drug misuse	Non-medicinal use of illicit drugs.
Effect size	A measure of the amount of change in outcome between treatment groups and control groups.
Externalising behavioural problems	Problem behaviours that are directed toward the external environment, or that manifest themselves through outward behaviour, most often involving negative or aggressive acts. Examples of externalising problems include aggression, conduct problems/disorder, violence, and antisocial behaviour problems.
Family functioning	A collection of effective behaviours between family members, including parents and children, that improves the functionality of the family unit (as opposed to dysfunction). It includes interactions and relationships within the family, particularly levels of conflict and cohesion, adaptability, organization, and quality of communication.
Intact couple	A couple (either married or unmarried) in which the partners have not divorced or separated.
Intensive case management (ICM)	An approach wherein care and support is delivered to a recipient in an in-depth way, e.g. a number of hours each day for a number of weeks. This is often undertaken by one team with a fairly small caseload and can be delivered over an extended period. It can involve support being available for 24 hours a day.
Internalising behaviour problems	Problem behaviours that are focused inwards, or that act as a method of coping with stress through negative feelings directed towards the self. Examples of internalising behaviours include anxiety, depression, and self-harming behaviours, including substance misuse.
Intervention	A programme, service or practice aimed at improving outcomes for participants.
Literature review	A comprehensive survey of the literature on a given research topic.
Longitudinal study	A study in which information is collected from the same study groups at different points in time, in order to examine changes over time. This is in contrast with cross-sectional studies, which collect data across different study groups at the same point in time.
Meta-analysis	A statistical technique that combines and analyses data across multiple studies on a topic.
Mixed-method study	A study combining quantitative and qualitative methods.
Motivational interviewing (MI)	A guiding style used to engage clients, draw on their strengths, aspirations and motivations for change and promote independent decision making in order to alter their behaviour.
Multi-agency working	An approach involving co-operation between different agencies in the delivery of support for an individual, based upon information sharing, joint decision making and co-ordinated intervention.
Non-dependence	Any level of alcohol or drug misuse which does not meet the diagnostic threshold for dependency or dependent use.
Outcome	The primary short- and long-term goals of an intervention.
Parental conflict	Conflicts that occur between parents/carers that are frequent, intense and poorly resolved.
Parenting practices	The specific behaviours that parents use to parent their children.
Parenting programmes	Support aimed at improving the knowledge, skills, attitudes and/or behaviours of parents in the raising of their children.
Protective factor	A factor that is associated with reduced potential for negative outcomes - for example, a positive parental-child relationship. This is in contrast with a risk factor.
Psycho-education	A collection of therapeutic methods, which integrate psychotherapeutic and educational interventions.
Qualitative study	A study grounded in research methods that produce non-numerical information, generated largely through observations, interviews, and focus groups.
Quantitative study	A study grounded in research methods that produce numerical data, which can be used in statistical analyses.
Quasi-experimental design (QED)	A type of experimental design that does not use randomisation to assign participants to a treatment and control group.
Randomised control trial (RCT)	A type of study design in which participants are randomly assigned to either one or more treatment groups and a control group to determine the efficacy of a treatment.
Rapid evidence assessment	A type of review that involves a more structured and rigorous search and quality assessment of the evidence than a literature review; it consists of a short but systematic assessment on a specific research topic.
Relationship distress	When either parent in a couple-parent family states that most or all of the time they consider divorce, regret living together, quarrel, or ‘get on each other’s nerves’.
Risk factor	A factor that is associated with increased potential for negative outcomes. This is in contrast with a protective factor.
Skills training	A collection of therapeutic methods that focus on providing people with specific skills, often through teaching, observation, discussion, and practice.
Socio-economic status (SES)	A measure of an individual’s combined economic and social status. Three common measures include education, income and occupation.
Substance abuse	A maladaptive pattern of drinking/drug use, leading to clinically significant impairment or distress, as manifested by at least one related problem in a 12-month period (e.g. failure to fulfil major role obligations), without the criteria for dependence having been met.
Substance misuse	Either alcohol use above low risk levels or non-medicinal use of illicit drugs.
Systematic reviews	The use of consistent and explicit methods to perform a comprehensive literature search, critical appraisal, and summary of all the published information surrounding a specific topic.
Uncontrolled pre-post study	A study that examines whether participants in an intervention improve or regress during the course of the intervention, and then attributes any such improvement or regression to the intervention, without the use of a control group.

Summary

Overview

There is a growing body of evidence about the impact on children of parental conflict and of substance misuse when experienced independently of one another. There is emerging evidence to suggest that when parental conflict and substance misuse coexist, the risk to children may increase, but this remains an understudied area. The Department for Work and Pensions (DWP) has commissioned this literature review in order to better understand the nature of this interrelationship, as well as how to mitigate any negative impact on children. This research builds on DWP’s analysis on the impact of multiple disadvantages in the Improving Lives: Helping Workless Families strategy document (2017a) and is designed to help inform the Reducing Parental Conflict programme (RPC programme) and additional funding with the Department of Health and Social Care and Public Health England (PHE) to help children with alcohol dependent parents.

For the purposes of this review, substance misuse includes both alcohol and drug misuse. It is noteworthy, however, that the majority of the studies identified (particularly within section 2 of the review) focused on alcohol use alone.

This literature review answers the following key questions, with a view to informing decision making in this area of policy:

• What is the relationship between substance misuse and parental conflict, and how do these coexisting factors impact on children?

• What interventions or elements of interventions appear to address parental conflict combined with substance misuse, and mitigate the impact on children?

• What characteristics of effecti.ve practice can be identified across interventions?

In addition, the review identifies where gaps exist in the evidence base and where these may need to be supplemented for the UK context.

Methodology

The literature review was undertaken by Cordis Bright. The review protocol and evidence assessment approach were agreed with DWP. The review protocol is presented in full in Appendix 1. The report examines 66 sources, drawing in particular from studies from the UK, USA and Australia.

Key findings: Understanding the impact of parental conflict and substance misuse on children

The nature of the relationship between substance misuse and conflict

There is consistent evidence of an association between substance misuse and parental conflict. While most recent studies focus on alcohol misuse, findings extend to substance misuse more broadly.

Some studies point to this association being causal, with one leading to the other. Most longitudinal studies support the view that substance misuse increases the incidence of parental conflict. That said, there are other studies that highlight how parental conflict can lead to substance misuse. In all cases there is less evidence regarding the mechanism by which one leads to the other and how it interacts with other stressors. The relationship is likely to be complex.

The risk posed to children

When parental substance misuse and conflict coexist, the risk of poor outcomes for the child is greater than when either is experienced alone.

There is some qualitative evidence to suggest that the increased risk to the child is incurred due to their increased exposure to conflict (as a result of parental substance misuse). There is stronger, but still mixed, evidence that the increased risk to the child is incurred via the combined impact of parental conflict and substance misuse on parenting practices and family functioning.

The nature of the impact on children

The nature of the negative outcomes for children in families experiencing both substance misuse and parental conflict appears to be the same as for those in families experiencing either substance misuse or parental conflict alone, i.e. mainly externalising or internalising behaviours. There is, however, consistent evidence that children affected by both parental substance misuse and conflict are more at risk of presenting these behaviours. No studies examined whether the behaviours presented by these children are more negative. Overall, there is no evidence for a ‘syndrome’ for children affected by parental substance misuse and conflict, as distinct from any other high-risk group.

The impact of other disadvantage

A number of other stressors (including housing, financial instability, crime, schooling or parental mental health) can act cumulatively to increase a child’s risk of negative outcomes. Children affected by parental substance misuse are also more likely to experience these additional stressors. The mechanism for why this might be (i.e. whether a causal relationship exists between substance misuse, crime and poor finances and in what direction) was not thoroughly explored in the literature reviewed.

Gaps in the evidence

The review encountered the following gaps in the evidence base:

• the prevalence of coexisting parental substance misuse and conflict

• the differential impact of drug and alcohol misuse on conflict and child outcomes, and the impact of different types of drugs

• the impact of substance misuse on the form and nature of parental conflict

• the sociodemographic characteristics of families experiencing both parental conflict and substance misuse

Inconclusive evidence was found for the differential impact of paternal and maternal substance misuse on conflict and child outcomes. Evidence for the impact of the child’s gender on the nature of outcomes experienced was also inconclusive.

Key findings: Interventions for tackling parental substance misuse and conflict and their relative effectiveness

The review identified few interventions explicitly aimed at tackling both substance misuse and parental conflict. As a result, this section has been widened to include studies that examine the impact of substance misuse interventions on parental conflict and on children’s outcomes (as well as substance use). No parental conflict interventions that, in turn, have an impact on substance misuse were identified. In addition, this section examines the impact of identified interventions on problematic parenting practices and family functioning.

Effective interventions

There is consistent evidence that behavioural couples therapy (BCT) results in a greater and longer-lasting reduction in substance use than individual behavioural therapy, and also improves relationship satisfaction and functioning in intact couples. There is also some evidence that BCT can improve outcomes for the couple’s children.

There is some evidence that the involvement of the whole family in substance misuse treatment can increase treatment engagement rates and lead to greater reductions in substance misuse than treatment delivered to the individual alone. There is more mixed evidence for the effectiveness of whole-family interventions on family functioning and there remains a lack of evidence regarding what form of family involvement is most effective.

How interventions create impact

The review identified that interventions often helped to develop the following set of skills in parents and children:

• helping parents to take responsibility for their actions and to understand the impact of their actions on their families

• improving communication between a couple and within the family as a whole

• skills training focused on emotional coping strategies, both to manage triggers to substance use and to improve parenting practices and conflict management.

The development of these skills was shown by studies to help improve outcomes relating to substance use, parental conflict, parenting practices and child development simultaneously.

Gaps in the evidence

More UK randomised control trials (RCTs) are necessary to determine the impact of interventions to tackle substance misuse and/or parental conflict in the UK context, as are studies with a focus on the long-term outcomes for children.

Key findings: Characteristics of effective practice

While successful interventions take many forms, and there are no definitive rules for ‘what works’, our review highlighted a number of considerations and common themes relating to design and delivery which influence the effectiveness of interventions.

Intervention timing and sequencing

Early intervention has consistently been shown to be important in preventing adverse outcomes for children affected by both parental substance misuse and conflict. There is also consistent evidence that tackling parental substance misuse and parental conflict/parenting within an integrated intervention is an effective approach.

Engagement and retention

Common barriers to accessing both substance misuse and parental conflict interventions include: a lack of recognition of the problem or motivation to change; stigma surrounding substance misuse and/or conflict and receiving help from statutory services and; difficulty accessing support due to its location, timing, the need for childcare or cost. Interventions can increase participation rates by providing parents with food, transportation and child care during sessions, or delivering sessions in the participant’s home.

Sociodemographic characteristics of target group

Interventions may need to be tailored if they are to engage with and work effectively for participants of different age, gender, ethnicity and socio-economic status. The literature lacked conclusive evidence about how best to engage and support these various groups, however, particularly LGBTQ+ couples and divorced or separated couples.

Intensity and length of intervention

There is consistent evidence for the positive impact of intensive case management (ICM) on substance use of participants and wider family functioning. Evidence is more mixed for the impact on child outcomes. There is also some evidence that extended interventions are more effective for high-risk substance misusers and those in greater relationship distress.

Format of intervention

Interventions should consider which intervention format is most appropriate for their target population and priorities. There is, for example, some promising evidence that group-based interventions involving multiple families can be beneficial for the children and families of those affected by substance misuse.

Techniques employed

Various techniques and therapies can be used successfully within substance misuse interventions, and interventions should consider which combination they should employ. There is, for example, some evidence that motivational interviewing can increase subsequent retention in substance misuse interventions when combined with BCT.

Multi-agency working

Multi-agency working can help to ensure that the full range of needs for the individual and the family are addressed and that support is co-ordinated.

Gaps in the evidence

The review encountered the following gaps in the evidence base:

• interventions targeting non-dependent substance misuse

• the impact of various sociodemographic characteristics, including socio-economic status, sexuality and whether a couple is intact or separated/divorced, on access, retention and outcomes for participants in substance misuse interventions

Future research should attempt to isolate the particular element(s) of an intervention’s format or content which make it successful.

1. Introduction

1.1 Research context

In April 2017 the Department for Work and Pensions (DWP) set out new analysis on the impact of multiple disadvantages in the ‘Improving Lives: Helping Workless Families’ strategy document, showing that poor relationships between parents can damage children’s short-term and long-term wellbeing. ‘Improving Lives’ led to the Reducing Parental Conflict programme (RPC programme), a £39 million initiative to support parents in conflict, which is in the process of being implemented across four local areas consisting of 31 local authorities.

A growing evidence base also exists around the prevalence of substance misuse in family breakdown and the impact that it can have on child outcomes. Treatment for substance misuse can improve child outcomes, but attention to parenting and parental conflict within substance misuse treatment has so far been limited.

In response, in April 2018 the government announced new support to help children with alcohol dependent parents. The programme was backed by a three-year £6 million joint fund from the Department of Health and Social Care and DWP working with Public Health England (PHE). The aim of the funding was to help identify at-risk children more quickly and provide them and their families with rapid access to support and advice. The package of measures includes:

• £4.5 million Innovation Fund for local authorities to develop plans that improve outcomes for children; support to address parents’ alcohol issues and reduce parental conflict

• £1 million to build capacity nationally to better identify and support children of alcohol-dependent parents, and tackle conflict within families, through voluntary, charitable and other not-for-profit organisations

• £500,000 to expand national helplines for children with alcohol-dependent parents

Though there is a growing body of literature and policy in relation to addressing the independent effects of parental conflict and substance misuse, there is less focus on their co-occurrence. In light of this, DWP commissioned this literature review in order to better understand the nature of this interrelationship, as well as how to mitigate the negative impact on children.

This literature review answers the following key questions, with a view to informing decision making in this area of policy:

• what is the relationship between substance misuse and parental conflict, and how do these coexisting factors impact on children?

• what interventions or elements of interventions appear to address parental conflict combined with substance misuse, and mitigate the impact on children?

• what characteristics of effective practice can be identified across interventions?

In addition, the review identifies where gaps exist in the evidence base and where these may need to be supplemented for the UK context. The evidence and learning from this review will be used to support the RPC programme and inform the development and testing of successful interventions in this area.

1.2 Methodology

1.2.1 Overview of methodology

This literature review deployed a rapid evidence assessment methodology. A review protocol was agreed in partnership with DWP (see Appendix 1). The review protocol was used to develop a long-list bibliography of sources that might be relevant to the review. This was distilled to a short-list with priority given to research that deployed the most robust methodologies, in line with the Scientific Maryland Scale. These sources were then used to generate evidence against each of the key research questions.

In total, 66 sources were examined, drawing in particular from studies from the UK, USA and Australia. An overview of the data sources used by the UK studies is included in Appendix 4.

1.2.2 Overview of study limitations

Literature reviews of this kind have a number of limitations. These are detailed below.

• Firstly, there is a risk that not all relevant resources have been included. This is because the review (a) focused on resources published after 2014; and (b) prioritised the first 30 studies returned by each search. We mitigated this risk by asking DWP and other partners to review the bibliography and add any key reports that were deemed to be missing.

• Lack of high-quality UK studies and, as a result, possibility of lack of applicability of findings to the UK context. Few high-quality UK studies were identified as part of this rapid evidence review. We mitigated the risk of there not being enough studies to include in the literature review by also including research from other countries, especially the USA and Australia. Where there were gaps in the evidence, we added some lower-quality studies with a UK focus.

• Small evidence base about the co-occurrence of parental conflict and substance misuse. Where studies exist about co-occurrence, we have given this priority. However, in places we have supplemented this with evidence relating to either substance misuse or parental conflict.

• Differing definitions. Studies often used different definitions of substance misuse and/or considered a specific aspect of it (e.g. only alcohol misuse or only drug misuse). There is a risk therefore of findings being aggregated in a way that is not appropriate. In particular, most studies focused on the co-occurrence of parental conflict and alcohol use, meaning that in some sections of the report the evidence base relating to illicit drug use is limited. We have sought to mitigate this risk by being clear about which studies relate to substance misuse overall and which to specific types of substance misuse (e.g. alcohol and drugs).

2. Understanding the impact of parental conflict and substance misuse on children

2.1 Overview

Within this chapter, we provide a review of the evidence on the interrelationship of parental conflict and substance misuse, in order to better understand how these factors interact. We then go on to evaluate the evidence for the impact of these coexisting factors on developmental outcomes for children.

In line with Acquah et al. (2017: pp. 5) we define parental conflict as “conflicts that occur between parents/carers that are frequent, intense and poorly resolved.” ‘Parental conflict’ as a term encompasses a spectrum of behaviours and the evidence shows that impacts on children are not confined to parental conflict manifested as domestic abuse. Within this literature review we therefore define parental conflict as behaviours below the threshold of domestic abuse and examine them separately to domestic abuse^{[footnote 1]}. This aligns with the focus of the Reducing Parental Conflict programme. However, where there is valuable learning in the literature about the co-occurrence of domestic abuse and substance misuse, we have highlighted this in this review.

Some of the studies reviewed contained a focus on separated or divorced couples. We have included a discussion of this literature in Appendix 3, as the relationship between parental conflict and divorce is inconclusive.

In line with McGovern et al. (2018: pp. 5) we define substance misuse as “either alcohol use above low risk levels or non-medicinal use of drugs prohibited by law”. This definition encompasses a large range of patterns of substance use, and includes both dependent and non-dependent use. Where studies have assessed either alcohol or drug use exclusively, or a specific level of use, the study’s own terminology has been used. It is important to note that the studies reviewed within this chapter focused mainly on alcohol misuse. This limits our ability to draw out potential differences between the impact on outcomes for children where there is parental conflict combined with, on the one hand, parental drug misuse, and on the other, alcohol misuse (please see section 2.8 for a further discussion of this and other gaps in the evidence identified).

2.2 Key findings

The nature of the relationship between substance misuse and conflict

• There is consistent evidence of an association between substance misuse and parental conflict. Most recent studies focus on alcohol misuse but findings extend to substance misuse more broadly.

• Some longitudinal studies support the view that this association is causal, i.e. substance misuse increases the incidence of parental conflict. That said, there is little evidence regarding how substance misuse does this (i.e. directly or indirectly via its contribution to other stressors). Again, most recent studies focus on alcohol misuse.

• There is some evidence from a small number of studies for the reverse causal association, i.e. relationship conflict can result in the onset of substance misuse.

The risk posed to children

• When parental substance misuse and conflict coexist, the risk of poor outcomes for the child is greater than when either is experienced alone.

• There is some qualitative evidence that the increased risk to the child is incurred due to their increased exposure to conflict (as a result of parental substance misuse).

• There is stronger, but still mixed, evidence that the increased risk to the child is incurred via the combined impact of parental conflict and substance misuse on parenting practices and family functioning.

The nature of the impact on children

• The nature of the negative outcomes for children in families experiencing both substance misuse and parental conflict is the same as for those in families experiencing either substance misuse or parental conflict alone (i.e. externalising and internalising behaviours).

• There is consistent evidence that children affected by both parental substance misuse and conflict are more at risk of presenting externalising or internalising behaviours. No studies examined whether the behaviours presented by these children are more negative.

• There is an association between children exhibiting externalising and internalising behaviours and early-onset substance misuse and academic underachievement.

• There is no evidence for a ‘syndrome’ for children affected by parental substance misuse and conflict, as distinct from any other high-risk group.

The impact of other disadvantage

• A number of other stressors (including housing, financial instability, crime, schooling or parental mental health) can act cumulatively to increase a child’s risk of negative outcomes.

• Children affected by parental substance misuse are also more likely to experience these additional stressors.

• There is a lack of evidence for how parental substance misuse and conflict interact with these additional stressors.

Gaps in the evidence

The review encountered the following gaps in the evidence base:

• The prevalence of coexisting parental substance misuse and conflict.

• The differential impact of drug and alcohol misuse on conflict and child outcomes, and the impact of different types of drugs.

• The impact of substance misuse on the form and nature of parental conflict.

• The sociodemographic characteristics of families experiencing both parental conflict and substance misuse.

Inconclusive evidence was found for the differential impact of paternal and maternal substance misuse on conflict and child outcomes. Evidence for the impact of the child’s gender on the nature of outcomes experienced was also inconclusive.

2.3 Context

2.3.1 The scale of the problem

There has been increasing attention placed in recent years, in both research and policy, on children living in households with substance misusing parents. These children have been described as those living with ‘hidden harm’, as their families are frequently not known to services. The scale of this harm is becoming better understood (Laslett et al., 2015). The Children’s Commissioner’s Office (2019) has estimated that:

• 308,000 children in England live with at least one high risk drinker over 18 years old

• 167,000 children in England and Wales live in households that report use of a Class A drug

• 515,000 children in England and Wales live in households that report use of any drug

• 472,000 children in England and Wales live with an adult who has reported to be dependent on alcohol or drugs

New psychoactive substances, such as synthetic cannabinoids, also pose an increasing risk, as their prevalence and the dangers associated with them are currently not well understood (Velleman and Templeton, 2016).

In terms of the UK policy response, the 2015-2020 Troubled Families programme, developed by the Ministry of Housing, Communities and Local Government (2019), includes an emphasis on those experiencing substance misuse, as well as other problems. Public Health England (2018) have released guidance to help local areas identify families affected by parental substance misuse, with the aim of reducing the harm to children. The Scottish and Welsh governments have included in their alcohol

strategies the aim to support families affected by parental substance misuse, and Northern Ireland’s ‘New Strategic Direction for Alcohol and Drugs’ also contains this focus (Parliamentary Office of Science and Technology, 2018).

Separately, awareness of the risks and the prevalence of parental conflict among families has also been increasing. DWP statistics (2018) show that 11% of children in couple-parent families the UK are living with at least one parent reporting relationship distress. In the policy landscape, DWP (2019) has developed a Reducing Parental Conflict programme (RPC programme), which aims to encourage and support local authorities to integrate support to reduce parental conflict in their local services for families.

Less is known, however, about the prevalence of families facing both parental conflict and substance misuse. In fact, none of the studies that were reviewed provided an estimate of the prevalence of parental conflict and substance misuse. DWP is now seeking to address this within the RPC programme through its joint testing of innovative projects with DHSC and PHE. This literature review forms a part of the programme. The following sections examine the evidence for the impact of the coexistence of these two factors on children and families, with a view to ascertaining whether policy should seek to tackle both simultaneously.

2.3.2 What do we already know about the independent effects of parental conflict or of parental substance misuse on children?

The negative effects on children of living with a substance misusing parent are well documented, and include an increased risk of externalising and internalising behavioural problems (see section 2.6.1 for further information), cognitive impairment, physical and mental health problems, and problematic substance misuse, as well as a range of other impacts (Velleman and Templeton, 2016; Finan et al., 2015; Jennison, 2014). Of these adverse outcomes, an evidence review conducted by McGovern et al. (2018) found that the strongest evidence for the influence of parental substance misuse was in relation to its impact on child substance misuse, as well as externalising behaviour (aggression, antisocial behaviour, etc.). A systematic review conducted by Asmussen and Brims (2018) supports this finding.

Recently, there has been an increase in the literature examining the impacts of parental conflict on outcomes for children (Harold et al., 2016; Sellers, 2016)^{[footnote 2]}. As early as six months old, children demonstrate signs of distress at witnessing parental conflict, including increased heart rate. Up to five years old, children show distress through crying, acting out or withdrawing into themselves (Harold et al., 2016). In the longer term, children who have experienced parental conflict are at increased risk of externalising and internalising problems, academic problems, physical health problems and social and interpersonal relationship problems which can impact on romantic relationships (Harold et al., 2016).

There is, therefore, substantial overlap in the range of outcomes experienced by children exposed to parental substance misuse and those exposed to parental conflict (as listed in Velleman and Templeton, 2016; Finan et al., 2015; Jennison, 2014; McGovern et al., 2018, Asmussen and Brims, 2018; Harold et al., 2016 and Sellers, 2016). In summary, these adverse outcomes include:

• impaired cognitive ability

• physical health issues

• impaired social functioning (for example increased conflict with peers)

• internalising problems – withdrawal, low self-esteem, anxiety, depression

• externalising problems – behavioural issues, antisocial behaviour, aggression

• reduced academic attainment

• future relationship instability

• substance misuse

Less is known, however, about the combined impact of parental conflict and parental substance misuse (i.e. where these factors coexist), and the nature of their interrelationship. The rest of this chapter presents a summary of the evidence regarding the relationship between substance misuse and conflict, and what is known about how the experience of a child changes when they are exposed to both.

2.4 The nature of the relationship between parental substance misuse and parental conflict

2.4.1 The association between substance misuse and parental conflict

Most studies about the relationship between substance misuse and parental conflict are focused on alcohol use. For instance, a study by McLaughlin et al. (2015), which analysed data from the Belfast Youth Development Study and family survey datasets for 4,500 young people, found a significant relationship between the frequency of arguments between parents and their Alcohol Use Disorders Identification Test (AUDIT) scores. In addition, marital satisfaction scores declined as AUDIT scores increased. Another study by Hutchinson et al. (2014) highlighted that men who were married or were cohabiting with their partner and were receiving treatment for alcoholism reported high levels of discord and non-violent conflict with their partner.

Several cross-sectional studies confirm that there is a link between alcohol use and marital or relationship conflict and dissatisfaction and posit that this also exists for substance misuse generally (e.g. Siegel, 2014; Harold et al., 2016).

The question of whether a causal relationship exists remains less clear, as fewer studies go beyond establishing an association to examine the nature of the interaction. The following section presents a summary of the evidence from those that do.

2.4.2 Substance misuse as the cause of parental conflict?

Studies that examined whether there was a causal link between substance misuse and relationship conflict were a mix of literature reviews and mixed-methods research and relate predominantly to alcohol misuse.

McLaughlin et al. (2015) state that parental alcohol misuse brings disruption to the family through creating marital distress, which often in turn leads to separation and divorce. Laslett et al. (2015) similarly suggest that the effect of alcohol use on families includes arguments (both between parents and parent-child), disharmony, divorce and domestic abuse. Their cross-sectional study of 446 families in Australia found that the most commonly reported harm caused by an identified problematic drinker, as reported by 63% of respondents, was involvement in ‘a serious argument that did not involve physical violence’.

There is some evidence from longitudinal studies, and in particular from epidemiology and treatment settings, to reinforce this causal relationship. A literature review conducted by Hutchinson et al. (2014) found that alcohol abuse by one partner predicts later marital problems for the couple. One study of newly-wed couples, for example, conducted at time of marriage and at their one-year anniversary, found that alcohol dependence in men predicted lower marital satisfaction among their wives at follow-up (although alcohol consumption and binge drinking did not) (Hutchinson et al., 2014).

Evidence suggests that discrepant levels of alcohol use between partners, for example if one partner were to have an alcohol use disorder when the other did not, is a greater predictor of relationship breakdown than actual drinking levels. When levels of alcohol use are congruent, meaning that partners drink together and at a similar level (including when both are dependent), a positive influence can be seen on marital satisfaction (Hutchinson et al., 2014).

In relation to whether there is a causal relationship between other types of substance misuse (e.g. drug misuse) and parental conflict, our review did not identify any recent studies. That said, Harold et al. (2016) cite a study from 2004 (outside of our review parameters but highlighted here for information) highlighting that drug abusing fathers are likely to be the catalyst and cause of relationship conflict. This suggests that a similar association exists with drug misuse as with alcohol misuse and relationship conflict.

Only a limited number of studies attempted to go beyond establishing a causal link between substance misuse and parental conflict, to examine what the mechanism explaining this link might be. As above, these studies were focused on alcohol misuse. McLaughlin et al. (2015) provides some support for the suggestion that alcohol in itself can be the cause of arguments in couples in which there is a substance abusing partner. The study identified a significant relationship between parents’ AUDIT scores and their reporting that arguments were caused by drinking. Of respondents, 13% stated that alcohol was sometimes either the cause of argument or made an argument worse, while 4% reported that it often was, and 4% reported that it almost always or always was. In support of this, Hutchinson et al. (2014) report that couples seeking marital therapy in Australia frequently report alcohol problems, most often in the male partner, as a cause of conflict.

The McLaughlin et al. study also asked about the frequency of arguments caused by their children and by money. ‘Problem drinkers’ (those engaging in any form of hazardous drinking, harmful drinking, or those experiencing alcohol dependence or alcohol use disorders) were twice as likely to report that they ‘often’ fight over the children (12% vs 6% of non-problem drinkers), and over three times as likely to ‘often’ fight over money (14% vs 4% of non-problem drinkers). This might suggest that alcohol use can indirectly lead to arguments between couples, through creating financial pressure or through causing problems regarding children in the family. There is some support for this conjecture in other literature, as parents with substance misuse issues may use a higher proportion of the family’s resources to source alcohol or drugs, and are also at an increased risk of neglecting their children (Ward, Brown and Hyde-Dryden, 2014). It is often difficult to ascertain whether the negative behaviours exhibited by substance misusing parents, for example being more critical and disagreeable, which may cause or exacerbate conflict, are unique to substance misusing couples or are attributable to the presence of these other stressors (Ladd and McCrady, 2016). This relationship requires more thorough exploration in future research.

2.4.3 Bidirectional relationship between substance misuse and conflict

There is other evidence to suggest that the causal relationship between substance misuse and conflict may not only be unidirectional, as a number of studies have also found relationship conflict to predict the onset or resumption of substance misuse. Again, the evidence for this relationship in the studies reviewed related to alcohol use. For instance, prospective community studies have shown baseline marital dissatisfaction to be associated with a 3.4 times increase in the likelihood of alcohol use disorder after 12 months (Hutchinson et al., 2014).

For those who have a history of alcohol misuse, evidence suggests that relationship conflict can predict a relapse. Relationship problems, and the emotional distress that these problems can cause, have been found to link to relapse for women who misuse alcohol (Schumm et al., 2014). McCrady et al. (2016) support this finding, reporting that women who experience alcohol use disorders are often found to report relationship difficulties as a precursor to their initial alcohol use as well as any relapse. As in these cases the alcohol misuse pre-existed the conflict, it cannot be said that the conflict was the sole cause of its onset. Rather, these findings suggest that conflict may increase the risk of alcohol misuse in those who already have a history of it.

While there is less evidence to support conflict causing alcohol misuse than the other way around, these findings do suggest that alcohol misuse (and probably substance misuse more broadly) and relationship conflict can have a dynamic relationship and that each can contribute to the other given different circumstances.

2.4.4 The relationship between substance misuse and domestic abuse

Whilst research on substance misuse and parental conflict is focused on alcohol misuse, the research on domestic abuse (DA) (Laslett et al., 2015; Siegel, 2014) encompasses both alcohol and drug misuse and highlights similar findings to those explored above.

A US study presented findings from a national survey which showed that 17% of parents experiencing DA also had a problem with substance misuse (defined here as use of alcohol or drugs that impairs functioning and ability to act as a caregiver) (Victor et al., 2018). Another US study has shown that DA is particularly prevalent in families with excessive-drinking husbands and light-drinking wives (Siegel, 2014). In the UK, a study using a sample of 223 men receiving treatment for substance use (predominantly alcohol, crack cocaine and heroin) found that 77.3% of participants had perpetrated intimate partner violence (Gilchrist et al., 2016).

Again, establishing a causal relationship between substance misuse and DA is more difficult. When substance misuse is seen as the cause, some of the potential mechanisms include the cognitive disruption it causes, or a ‘loss of control’. While some studies have presented evidence for such a relationship, studies have not managed to exclude the possibility that an unassessed third factor may account for both outcomes (Hutchinson et al., 2014). Laslett et al. (2015), argue that while in some cases DA may not have occurred without the substance misuse (in this case drinking) that preceded it, it can rarely be said to be a necessary or sufficient cause.

There is more evidence to suggest that substance misuse may exacerbate or increase the severity of DA. Laslett et al. (2015) find that binge drinking (i.e. heavy episodic periods of drinking), is associated with more aggression within conflict and an increased severity of injury. They also find that aggression tends to be more severe when one or both of the partners involved is drinking. Hutchinson et al. (2014) support this notion, suggesting that the level of alcohol use relates to the level of domestic abuse experienced, rather than the incidence of episodes.

2.5 The risk posed to children

As noted above, it is well established in the literature that both parental substance misuse and parental conflict, independently of one another, can have considerable adverse effects on children. Less is known about their combined impact on children. The following sections explore this further.

2.5.1 Parental conflict as a risk factor for children experiencing parental substance misuse

In much of the literature, parental conflict is discussed as a risk factor which when experienced alongside parental substance misuse significantly increases the risk of a child achieving negative outcomes (see for example Velleman and Templeton, 2016). What this looks like for children is explored further in section 2.6. However, it is noteworthy that the scale of this increased risk is rarely quantified in recent literature. This is a gap which future research may seek to address. The research also suggests that this risk extends into children’s outcomes in adulthood: McLaughlin et al. (2015), to take one example, found family conflict to predict adult alcohol problems in the children of individuals with alcohol use disorder.

While the potentially negative impacts on children of having substance misusing parents are well established, there remain a number of children who still achieve good outcomes despite exposure to this behaviour (McLaughlin et al., 2015). The mechanism through which some children experience poor outcomes and others don’t is thus an important one to understand, and it appears that the presence or absence of parental conflict may be significant here.

This has led some authors to focus on ‘protective factors’ rather than ‘risk factors’, i.e. how a positive parental relationship can act as a buffer against the negative effects on children of a substance misusing parent (McLaughlin et al., 2015). McGovern et al. (2015) argue that in policy the language of protection is preferable to the language of risk, as protective factors can be viewed as a possible mechanism by which interventions can aim to positively enhance a child’s resilience from harm. Beyond the parental relationship, protective factors can include the internal characteristics of the child, their positive engagement in a range of activities, or a close bond with at least one adult figure (potentially outside the family) (McLaughlin et al., 2015). Particularly in the early years of development, however, the literature suggests that family-level factors remain the most important in preventing or moderating negative outcomes in children affected by parental substance misuse (Velleman and Templeton, 2016).

Beyond understanding what factors are likely to put children particularly at risk of experiencing negative outcomes, or those which might protect them, it is also important in informing the design and delivery of interventions to understand the processes through which this increased risk is incurred (Harold et al., 2016; Sabates and Dex, 2015). The following sections discuss two potential mechanisms through which exposure to parental conflict may increase the risk posed to children of substance misusing parents. These are as follows:

• substance misuse can cause or exacerbate conflict, to which child exposure is a harm in itself

• substance misuse and conflict can together impact on parenting and family functioning, which can have a negative impact on children

While this is not an exhaustive account, these were the mechanisms for which the most evidence was found in the literature. It should be noted, however, that the evidence in the literature for the impact of parental substance misuse and conflict on the children exposed to the conflict was mainly qualitative. The literature contained more evidence for the impact of substance misuse and conflict on parenting and family functioning. It appears reasonable to assume, however, that a complex and dynamic series of effect pathways, including both of those outlined below, are acting on children affected by both parental substance misuse and conflict. These pathways resist simplification.

Exposure to conflict as a harm in itself

There is some evidence, albeit largely qualitative, to suggest that exposure to conflict resulting from or exacerbated by substance misuse, has a greater impact on the child than the substance misuse itself (Laslett et al., 2014; McLaughlin et al., 2015).

One cross-sectional study of 2,649 Australian families, found that where one or more parent misused alcohol, the most common harm to children reported by parents was witnessing verbal or physical conflict (in this study, this incorporates parental conflict and domestic abuse) between parents. The most common harm reported by parents who stated that their child experienced ‘a lot’ of harm, was witnessing conflicts between their parents. For those who were deemed to have been harmed only a little, the most common reported harm was witnessing drinking or inappropriate behaviour. This suggests that witnessing conflict was perceived by parents to be more harmful to the child than witnessing drinking (Laslett et al., 2014). While useful as an insight into the perception of parents, this study is limited by its sole reliance on the judgement of the parents regarding the nature and impact of harms felt by children.

Evidence from qualitative studies conducted with the children of substance misusing parents also supports this notion, as children were found to be more concerned about parental arguments than they were about their parents’ drinking (McLaughlin et al., 2015). Children have reported feeling fear, anger, frustration and sadness about their parents’ conflictual relations, as well as a lack of sleep and a disruption of their social life due to not wanting to bring friends home (Laslett et al., 2015). Behavioural problems, later alcohol and drug use or depression are also reported in the literature (Siegel, 2014).

Harold et al. (2016) report that substance misuse (including both drug and alcohol misuse) is associated with increased risk of poor child adjustment, due to the child witnessing a higher incidence of conflict, and sometimes physical violence. The study suggests that the impacts of parental conflict on children are worst when the conflict is “frequent, intense, and poorly resolved” (Harold et al, 2016: pp. 6). While the broader literature lacked evidence regarding the impact of substance misuse on the nature of parental conflict, there is more evidence to suggest that it may contribute to its incidence, and thereby the risk to the child (see also Laslett et al., 2015; McLaughlin et al., 2015 or; Hutchinson et al., 2014).

The impact on parenting and family functioning

There is different evidence to suggest that substance misuse and parental conflict may have the greatest impact on children indirectly, via their combined influence on parenting practices, family functioning, and the parent-child relationship. Studies, both qualitative and some quantitative, suggest that substance misuse alone can impact directly on parenting (for example by reducing parental monitoring and consistent discipline) but can also do so indirectly by creating or exacerbating parental conflict (McLaughlin et al., 2015; Siegel, 2014). Parental conflict then acts as a further stressor and cause of emotional distress in parents that ‘spills over’ into wider family functioning and parenting practices (as well as further substance misuse) (Hutchinson et al., 2014; Siegel, 2014; Harold et al., 2016). These findings emerged from a range of literature reviews and longitudinal studies.

Some of the impacts of substance misuse and parental conflict on families and on parenting listed in the literature include:

• worsening quality of parental monitoring

• reduced parental warmth

• poor parent-child relations

• reduced family cohesion

• negative family communication

The parental conflict literature suggests that adverse parenting practices tend to develop as parents engaging in conflictual relations with one another also become more hostile and aggressive in their interactions with their children, and less alert to their needs (Harold et al., 2016). Studies have shown marital conflict to predict lower levels of parental monitoring and a poorer parent-child relationship (Jennison, 2014; Harold et al., 2016). This effect is likely to be compounded when parents are experiencing conflict as well as substance misuse, due to the proven tendency of substance misuse to exacerbate conflict.

For the children of substance misusing parents, problematic parenting practices have been found to predict worse outcomes in both the short and long term (Velleman and Templeton, 2016). Parental monitoring, for example, is usually an important means by which risky behaviour in adolescents can be moderated and harm prevented (McLaughlin et al., 2015; Jennison, 2014). In addition, poor parent-child attachment has been found to be more damaging to child mental health than exposure to parents’ alcohol use (McLaughlin et al., 2015). The risk of children experiencing poor parenting practices and the associated negative outcomes will increase where parental substance misuse and parental conflict coexist.

This mechanism has been described as an ‘indirect effects pathway’ and demonstrates the complex combination of factors which result in negative developmental outcomes for the child (McLaughlin et al., 2015; Hutchinson et al., 2014). It is increasingly recognised in the literature that family influences interact in a dynamic fashion and operate on children as ‘chain-of-event processes’, as opposed to an individual risk factor having a particular independent influence on the child (Sellers, 2016). This model draws on theories of human development, such as Brofenbrenner’s ecological model (1994), which argues that to understand behaviour and development processes you must understand the complex and dynamic interactions between individuals and their environments, in which the family is particularly important (Sabates and Dex, 2015). Sellers (2016) argues that this process-orientated model, taking into account a range of factors contributing to ‘family functioning’, more realistically explains differences in child development than a ‘dogma-driven’ perspective focused on the influence of any given factor.

In order to protect children affected by parental substance misuse and conflict, therefore, it may be prudent as part of any intervention to seek to consolidate or improve parenting practices and family functioning as well. Alongside the swift resolution to interparental problems, Velleman and Templeton (2016) describe positive parenting, openness and good communication in the family and good parent-child relationships as the ‘roots of resilience’ for children affected by parental substance misuse.

A conclusive picture?

While there is some evidence to support the notion that substance misuse and parental conflict together increase the risk of poor outcomes for children by further degrading family functioning and parenting practices, the overall picture for this effect pathway remains inconclusive. One mixed methods study reviewed, for example, found that while there was a clear association between the frequency of parental arguments and the parents’ AUDIT scores within the cohort, no association was found with other family variables such as parental monitoring, or with child outcomes. The authors note this result as surprising, however, and suggest that it might be due to a limitation of the data (McLaughlin et al., 2015). Similarly, another study noted that while there was substantial cross-sectional evidence to suggest that families affected by marital distress together with alcohol misuse demonstrate more negative communication than those families managing one or the other, this evidence was not enough to prove a causal relationship. More longitudinal studies or proper control for the full range of variables which could confound the results would be required to do so (Hutchinson et al., 2014).

2.6 The nature of the impact on children

Based on the literature reviewed, it does not appear as if the nature of negative outcomes for children in families experiencing both substance misuse and parental conflict is different to those children in families experiencing either substance misuse or parental conflict alone, i.e. mainly either externalising or internalising behaviours. The literature does suggest, however, that the risk of these negative outcomes is greater for those children in families with both substance misuse and parental conflict. No studies examined whether the behaviours presented by children in families with both substance misuse and parental conflict are more negative.

2.6.1 Externalising and internalising behaviours

As previously noted, children affected by parental substance misuse or parental conflict (independently of one another) are more likely to possess tendencies towards externalising or internalising behaviours (Park and Schepp, 2015; Finan et al., 2015; Harold et al., 2016). However, these tendencies do not always translate into behavioural change (Charles et al., 2015). Where children are affected by coexisting parental substance misuse and conflict, evidence shows that the risk of their presenting externalising or internalising behaviours will increase. Substance misuse, it is suggested, predicts parental conflict and related parenting difficulties, which then combine to increase the risk of child externalising or internalising problems. These findings are drawn from a range of systematic reviews and literature reviews (Park and Schepp, 2015; Harold et al., 2016; Hutchinson et al., 2014).

One US study on the effect of parental drinking problems, quality of parental relationship and other family factors on child outcomes found some evidence to support this theory (Jennison, 2014). The longitudinal study made use of four subscales to measure the family environment, including one to measure parental relationship based on how often parents get along well, agree on rules, engage in arguments and how often the young person feels caught in the middle of the parents’ interactions. The study found a three times greater risk of truancy, absenteeism, suspensions and related school behaviour problems (behaviours associated with externalising tendencies) among young people whose biological father was a heavy drinker and where the quality of the parents’ relationship was poor. While this combination of variables had the greatest effect size of all those listed (including the biological father reporting alcohol problems within early life stages of the young adult), the effect sizes of father heavy drinking and low marital quality of parents independently of one another were not presented for comparison. Further longitudinal studies in the UK context would be helpful to better understand this relationship.

In addition, externalising and internalising behaviours in children are associated with early onset substance misuse, which is a strong predictor of later substance dependence (Siegel, 2014)^{[footnote 3]}. Siegel’s research, therefore, can be used to conclude that by increasing the risk of externalising and internalising behaviours, parental substance misuse and parental conflict increases the risks of these children experiencing early onset substance misuse and later substance dependence.

2.6.2 A ‘syndrome’?

While it is possible to identify some broad patterns of behaviours which children who experience parental substance misuse and conflict are at greater risk of developing, there appears to be no ‘syndrome’ for children affected by these coexisting factors. The outcomes experienced by these children are similar to those experiencing either parental substance misuse or parental conflict alone, meaning that they cannot be uniformly characterised as distinct from any other high-risk group (Hutchinson et al., 2014).

Moreover, children can experience a broad range of individual outcomes, which are also likely to be influenced by the severity of both the substance misuse and the conflict (although this relationship is understudied in the literature), as well as the presence of other stressors. The children affected by these experiences, therefore, should not be seen as a homogenous group with identical needs. Indeed, even within any one family, children have been found to respond differently to the same set of problems. Velleman and Templeton (2016) make the following point:

…children and families are unique, so rules about risks and outcomes are often not generalizable: it is unhelpful to look for specific and linear links between a particular problem/risk factor and particular negative outcome.

(Velleman and Templeton, 2016, pp: 109)

The following sections will assess the way in which a number of other factors, which children affected by parental substance misuse and conflict may also face, can act cumulatively to increase the child’s risk of experiencing negative developmental outcomes.

2.7 The impact of other disadvantage

Much of the literature discusses parental conflict and substance misuse alongside a number of other risk factors and stressful events which can impact upon a child’s developmental outcomes. This prompts the question of whether the combination of substance misuse and parental conflict is a uniquely damaging one for the children who experience it, or whether these are just two of a wide range of stressors which place children at risk.

2.7.1 Parental substance misuse combined with additional risk factors

A number of studies use parental substance misuse as the baseline for a child’s level of risk, and examine the impact of added stressors on this risk (see for example Velleman and Templeton, 2016; Park and Schepp, 2015; Charles et al., 2015). These studies, on the whole, support the notion that while parental conflict may exacerbate the risk of poor outcomes for children of parents with substance misuse problems, there are also a number of additional risk factors, both in the wider family environment and the lives of their parents, which together have a cumulative effect on children and increase the chance of their experiencing adverse psychological and behavioural issues.

For instance, Velleman and Templeton (2016) present a ‘cumulative stressors model’, in which the more risk factors children are subjected to, the more likely they are to experience poor outcomes. The authors suggest that while parenting and the family environment, which parental conflict forms a part of and has been shown to make worse, makes up one pathway through which children whose parents misuse substances are put at increased risk, there is also another pathway made up of additional risks outside the family, for example association with the criminal justice system.

Park and Schepp (2015) similarly characterise ‘family-level factors’, including marital conflict and family conflict, as one of four levels of risk factors which can act to increase negative outcomes in children of alcoholics. The other three levels include parental factors (relationship between parent and child), individual level factors (the characteristics and attributes of the child), and social factors (including sociodemographic characteristics of the family and the wider social environment). Children of alcoholics, already vulnerable to achieving negative outcomes, are found to become increasingly vulnerable as they are exposed to additional risk factors.

Charles et al. (2015) depict a similar picture with regards to the risk of early substance use initiation among children with a family history of substance use disorders (FH+). FH+ children are deemed to be at risk of developing substance misuse issues due to a genetic vulnerability, but this can be seen to increase with increased exposure to childhood stressors and adversity. In their study of US children, Charles et al. (2015) found that more FH+ children reported stressors in the areas of housing, family, school, crime, peers and money, than children without a family history of substance use (FH-) No differences were found in abuse, health and familial deaths. FH+ children experienced more cumulative stress, and the cumulative severity of the stressors they experienced was also greater. This stress was found to be concentrated in particular domains, which include family (the measures for which included a question about whether the child’s parents had ever had any problems getting along), but also crime and money. The results showed that increased exposure to stressors by FH+ children had an additive effect, with every ten-point increase in stressor severity at study entry increasing the likelihood of early substance use initiation in early adolescence by 16%. This is particularly marked as prior to any stress exposure FH+ adolescents are four times more likely than FH- children to begin substance use.

Finally, literature in the UK on Adverse Childhood Experiences (ACEs) further supports the idea of cumulative impact on children’s outcomes of multiple challenges faced by a family^{[footnote 4]}. For instance, Hughes et al. (2016) describe a ‘dose-responsive’ relationship between ACEs and poor developmental outcomes for children, with a greater number of ACEs faced having a cumulative effect on the likelihood of health harming behaviours. Children, it is suggested, adapt to stressful home environments through developing heightened emotional and physiological stress response system, a change which can lead to heightened levels of anxiety and risk-taking behaviour (Ford et al., 2016). The cumulative effect of ACEs is supported by the Bellis (2016) study, which found that, compared to those with no ACEs, people who experienced four or more were four times more likely to be a high risk drinker, 11 times more likely to have smoked cannabis, 15 times more likely to have committed violence against another person in the last 12 months and 16 times more likely to have used crack cocaine or heroin. Ford et al. (2016) found that those with four or more ACEs were twice as likely to be a binge drinker. Prevalence of cannabis use, early sexual intercourse, low mental wellbeing scores and low life satisfaction also increased as ACE count increased. Hughes et al. (2016), in their nationally-representative survey of English households, found a strong association between ACE count and markers of low mental wellbeing.

These studies provide support for the notion that children who may be facing substance misuse and parental conflict are also likely to be facing a wide range of additional stressors, including those related to crime and family finances. The mechanism for why this might be (i.e. whether a causal relationship exists between substance misuse, crime and poor finances and in what direction), was not thoroughly explored in the literature reviewed, and may benefit from further research. This evidence does suggest, however, that these stressors act to cumulatively increase the risk faced by children, and so does not necessarily support the notion that the risk posed to children by the combination of parental conflict and substance misuse is unique.

2.7.2 Parental mental health

Mental health issues in parents is one of the most frequently reported stressors for children in the UK. One study examining the prevalence of 10 different risk factors^{[footnote 5]} in children, using data from the UK Millennium Cohort Study, found that parental depression was the risk factor with the highest prevalence rate. Parental depression was found to occur in all of the most frequently reported four-risk combinations^{[footnote 6]}, as well as the most common six and seven-risk combinations and three out of five of the most common five-risk combinations (Sabates and Dex, 2015). A number of the studies reviewed also stressed the importance of parental mental health in determining outcomes for children. In particular, a strong association has been found between growing up in a house in which there is mental illness, and going on to develop mental illness as an adult (Hughes et al., 2016).

With regard to the specific interaction between mental health issues, substance misuse and parental conflict, Hutchinson et al. (2014) suggest that it is reasonable to assume that family conflict, as well as other stressors such as financial difficulties and parenting problems, are more likely to occur and be more severe when alcohol use coexists with other mental health problems in the parent(s). Parental mental illness, as well as parental conflict, has been shown to mediate the relationship between paternal drinking and poor parent-child relationship (Hutchinson et al., 2014). Separately, Harold et al. (2016) present evidence that parental depression is associated with an increased risk of depression in children, via the effect it has on parental conflict. DWP statistics (2017b) show a strong association between poor parental mental health and parental relationship distress, suggesting that children growing up with parents presenting anxiety and/or depression are more than twice as likely to also experience parental relationship distress.

An NSPCC (2018) report into children living in families facing adversity also contained an emphasis on parental mental health, which in combination with substance misuse and domestic abuse made up their definition of ‘adversity’. Their analysis of ChildLine contacts and counselling sessions suggests that children report these factors to be highly interrelated in family life. This might mean, for example, that parents with poor mental health may use substances as a way to cope, that this substance misuse may then lead to more conflict and domestic abuse, and that domestic abuse may contribute to the mental health problems.

While the exact nature of these interrelationships requires further exploration, it appears that an intervention aimed at improving parental substance misuse and or/conflict, may wish to consider the role played by parental mental health and how this might best be addressed.

2.8 Gaps in the evidence

This section presents a summary of the gaps in the evidence identified in sections 2.3 to 2.7:

• The scale of the problem: this review highlighted no studies about the prevalence of children living in families where there is both substance misuse and parental conflict.

• The relationship between substance misuse and conflict: only a limited number of studies went beyond establishing a causal link between substance misuse and parental conflict to examine what the mechanism explaining the link might be, i.e. whether substance misuse contributes to conflict directly, or indirectly via its contribution to other stressors such as financial difficulties.

• The risk posed to children: while various studies presented evidence that experiencing parental conflict alongside parental substance misuse significantly increases the risk of a child achieving negative outcomes, few sought to quantify the scale of this increased risk.

• The nature of the impact on children: there is evidence that children affected by both parental substance misuse and conflict are more at risk of presenting externalising or internalising behaviours. However, the review identified no studies which sought to examine whether the behaviours presented by these children are more extreme.

In addition, three further gaps in the evidence base are:

• the impact of different types and severity of substance misuse and conflict

• the characteristics of families experiencing conflict and substance misuse

• the impact of the gender of the affected parent and of the affected child

2.8.1 The impact of different types and severity of substance misuse and conflict

While this review considers ‘substance misuse’ overall, the majority of the literature reviewed within this chapter focuses on alcohol misuse in parents. What differences may exist in the parental conflict experienced by drug misusers and alcohol misusers, as well as users of different types of drugs, and the impact that this has on children, is currently not well known and requires further research.

The patterns of substance misuse which are affecting children and families, in particular the difference between dependent and non-dependent substance misuse, are also currently understudied (Laslett et al., 2015). There is some evidence to suggest that different styles of substance misuse may have different impacts on parental conflict and on the children of the family. One study of newly wed couples, for example, found that while alcohol dependence in men predicted lower marital satisfaction in their wives, alcohol consumption and binge drinking (defined here as consuming more than four standard drinks on a single occasion), did not (Hutchinson et al., 2014). In order to form firm conclusions, further research should seek to systematically examine the differing impact of the different patterns of substance misuse.

Harold et al. (2016) present evidence that conflict which is frequent, intense, and not successfully resolved has the most negative impact on the child. This is in contrast to conflicts which lack acrimony and are easily resolved. The way in which substance misuse may contribute to the nature and acrimony of conflict was not fully explored in the literature reviewed (which tended to focus only on the incidence of conflict), and so may benefit from further research going forward.

2.8.2 Characteristics of families experiencing conflict and substance misuse

Aside from including sociodemographic differences as control variables, the literature contained only limited explicit discussion of the characteristics of families experiencing both parental conflict and substance misuse.

Out of the studies reviewed, the only ones to compare the results found in different ethnic minority backgrounds were conducted in the US. Jennison (2014) was one such study, which found that the impact of a high conflict home life combined with parental drinking was greater on children from a minority ethnic background. Another study conducted by Waldron (2017), however, found that the combined impact of parental separation and alcohol misuse was similar across a cohort of European American and African American twins. This evidence appears inconclusive, therefore, and cannot necessarily be translated into the UK context.

The literature does contain some discussion of the prevalence of certain characteristics among families experiencing substance misuse issues. McLaughlin (2018), for example, argues that parents experiencing alcohol problems are more likely to also experience a range of other disadvantages, including drug misuse, unemployment (which in particular was shown to be associated with maternal alcohol abuse), parental mental health and parental hardship. Middle- and higher-income respondents are also reportedly less likely to report alcohol related harm to their children than those in lower income families. As noted previously, it appears likely that these factors are all closely interrelated and that no unidirectional causal relationship exists. None of the studies sought to ascertain whether any differences in these characteristics exist when substance misuse issues coexist with parental conflict.

For those families living with parental conflict, previous research conducted by the Department for Work and Pensions (2017) has found that relationship distress is three times as prevalent in workless families, compared to those in which both parents are working. In a report by the EIF, Acquah et al. (2017) note that economic disadvantage is associated with increased risk of poor parental relationship quality. The authors cite a longitudinal study of 400 couples, which showed economic pressure to increase the risk of relationship conflict and distress. Harold et al. (2016) argue, however, that parental conflict can also occur in households in which children would not otherwise be deemed at risk of adverse outcomes.

The literature on ACEs also contained some discussion of the characteristics associated with families experiencing a higher number of risk factors. One study, for example, found worklessness and a lack of basic skills in the family to be relatively low in prevalence in the families studied, but to be associated with many of the more common combinations of risk factors, although no causal relationship can be implied from this (Sabates and Dex, 2015). Another study found a slightly higher prevalence of four or more coexisting ACEs in the most deprived quintile of the individuals studied (Ford et al., 2016).

Again, evidence in this area is piecemeal, and absent in relation to families experiencing both parental substance misuse and parental conflict. More systematic research is required to elucidate whether or not there are particular characteristics associated with these families.

Within families, the characteristics of children likely to be at most risk of being adversely affected, including age and gender, is another important area where more research is required (Velleman and Templeton, 2016).

2.8.3 Gender of parent and gender of child

The need for more research into the different effects of living with maternal or paternal substance misuse problems is highlighted in much of the literature reviewed (see for example Velleman and Templeton, 2016). A number of studies have attempted to assess the different impact caused by paternal and maternal substance misuse on children, but the evidence remains inconclusive. While some studies report that maternal substance misuse has a greater impact on offspring outcomes than paternal misuse, others suggest the opposite (Keeley et al., 2015; Laslett et al., 2015).

There is even less evidence regarding the association between maternal or paternal alcoholism on conflict, and the different impact that this may have on children. There is evidence to suggest that women are more likely than men to drink in response to marital discord and stress, but as the different impact of maternal and paternal alcoholism on children is not clear, the implications of this finding for children are hard to know (Schumm et al., 2014; McCrady et al., 2016). Conversely, paternal substance abuse has been associated with a greater incidence of parental conflict and violence (Hutchinson et al., 2016). This implies that paternal substance misuse places children at a higher risk of emotional and behavioural problems, due to the strong association between parental conflict and the poor parenting practices which contribute to these outcomes in children (Harold et al., 2016; Hutchinson et al., 2014). The overall picture is therefore unclear, and it cannot confidently be claimed that either maternal or paternal substance misuse has a more damaging effect on the children involved. It is also unclear, and not addressed within the literature, whether observed differences may be due to the parent being the mother or father or rather due to their being the primary carer or not the primary carer.

With regard to the gender of the children concerned, a number of studies have compared male with female children of substance misusing or arguing parents, to assess their comparative vulnerability to experiencing negative outcomes (Park and Schepp, 2015). There is some evidence to suggest that girls are particularly at risk from problems in the family, including substance misuse and parental conflict. One study found that girls are at a higher risk of ‘interpersonal stress’ (no definition of which is offered in the study) as a result of a breakdown in family functioning (Finan et al., 2015). An Irish study on the impact of parental substance misuse on adolescent children found that parental problems were reported more frequently by girls than boys, perhaps suggesting that girls are more affected by these issues (Keeley et al., 2015). No clear picture has emerged here, however, as the results of studies have generally been inconsistent.

Other studies in the parental conflict literature suggest that it is the nature of the impact on boys and girls that is different, as opposed to there being a clear difference in severity. Boys, evidence suggests, are more likely to see conflict between their parents as a threat to themselves, whereas girls are more likely to see it as a threat to the family as a whole. This threat-based attribution on the part of girls can exacerbate symptoms of depression, whereas in boys it tends to exacerbate externalising behaviours (Harold et al., 2016; Sellers, 2016). Again, the way in which the additional challenge of parental substance misuse may contribute to these differences is not explicitly addressed.

More detailed studies are needed, therefore, to ascertain the differential vulnerability and nature of the impact felt by children of substance misusing parents who are engaged in conflictual relations. While gender was an issue focused on within the literature, no consistent picture has emerged, suggesting that future research may need to look beyond gender to assess what may affect how different children affected by parental conflict and substance misuse respond.

3. Interventions for tackling parental substance misuse and conflict and their relative effectiveness

3.1 Overview

This section highlights interventions which address parental conflict combined with substance misuse, and mitigate the impact on children. However, the review identified few interventions explicitly aimed at tackling both substance misuse and parental conflict.

As a result, this section has been widened to include studies that examine the impact of substance misuse interventions on parental and relationship conflict and on children’s outcomes (as well as substance use). No parental conflict interventions that, in turn, have an impact on substance misuse were identified. In addition, this section examines the impact of identified interventions on problematic parenting practices and family functioning.

The focus of this section is on parental or relationship conflict, as opposed to domestic abuse. Those studies which explicitly assessed the impact of particular interventions on domestic abuse are included in section 3.3.5. While the interventions detailed in other sections may also impact on domestic abuse, this is not an explicit aim of the programme or a focus of the studies included. The interventions examined include:

• substance misuse interventions delivered to the individual parent

• substance misuse interventions delivered to the couple^{[footnote 7]}

• substance misuse interventions delivered to the whole family (including children)

• parenting programmes for parents affected by substance misuse

• domestic abuse and substance misuse interventions

• substance misuse interventions delivered through the criminal justice system

• parental relationship interventions

This list is not mutually exclusive as some interventions may fall into more than one category. Within each category, we have sought to identify those interventions which are most effective in improving outcomes relating to substance use, the interparental relationship, parenting practices and child development.

A breakdown of the interventions included in this section, as well as an overview of their evidence base and effectiveness, is included in Appendix 5.

3.2 Key findings

Effective interventions

• Substance misuse interventions delivered to the affected individual can have a positive impact upon relationship outcomes as well as substance use.

• There is consistent evidence that behavioural couples therapy (BCT) results in a greater and longer-lasting reduction in substance use than individual behavioural therapy, and also improves relationship satisfaction and functioning in intact couples. There is also some evidence that BCT can improve outcomes for the couple’s children. There is evidence from a small number of studies that BCT combined with individual behavioural therapy can have the same or better effect on substance use than BCT alone, and responds to the preference of some women to receive treatment alone.

• There is some evidence that the involvement of the whole family in substance misuse treatment can increase treatment engagement rates and lead to greater reductions in substance misuse than treatment delivered to the individual alone. There is more mixed evidence for the effectiveness of whole-family interventions on family functioning. There remains a lack of evidence regarding what form of family involvement is most effective, in particular in improving outcomes for children.

• There is some evidence that the impact of combined substance misuse and parenting interventions on parenting practices is greater than from substance misuse treatment alone. The impact on substance misuse, however, remains the same as when parents attend substance misuse treatment alone.

There is evidence from a small number of studies that brief parenting skills interventions can encourage engagement in substance misuse treatment for parents.

How interventions create impact

The review identified that interventions often helped to develop the following set of skills in parents and children:

• Helping parents to take responsibility for their actions and understand the impact of their actions on their families can motivate parents both to reduce their use of substances and improve the quality of their relationships (both inter-parental and parent-child).

• There is consistent evidence that improving communication between a couple can help both to reduce relationship conflict and maintain reductions in substance misuse. There is also evidence from a small number of studies to suggest that the inclusion of communication training in whole-family interventions can improve family functioning and child behavioural problems.

• Skills training focused on emotional coping strategies can help parents to manage triggers to substance use, while improving their parenting practices and conflict management at the same time. There is also some evidence that providing coping skills to children can reduce their risk of experiencing negative outcomes.

The development of these skills was shown by studies to help improve outcomes relating to substance use, parental conflict, parenting practices and child development simultaneously.

Gaps in the evidence

More UK randomised control trials (RCTs) are necessary to determine the impact of these interventions in the UK context, as are studies with a focus on the long-term outcomes for children.

3.3 Effective interventions

The following section discusses interventions for tackling parental conflict and/or parental substance misuse which were identified within the literature, i.e.:

• substance misuse interventions delivered to the individual parent

• substance misuse interventions delivered to the couple

• substance misuse interventions delivered to the whole family (including children)

• parenting programmes for parents affected by substance misuse

• domestic abuse and substance misuse interventions

• substance misuse interventions delivered through the criminal justice system

• parental relationship interventions

3.3.1 Individual substance misuse interventions

This section is focused on interventions which are delivered solely to an individual parent affected by substance misuse. This includes substance misuse interventions tailored specifically for parents as well those aimed at adults more generally (but where the impact on parents has been assessed in the study).

McGovern et al. (2018) conducted a review of 7 trials of substance misuse interventions (2 QEDs and 5 RCTs) delivered to the affected individual, all of which had been adapted for a parent population. These interventions included those involving intensive case management, as well as psychological interventions (including brief motivational interviewing (MI), cognitive behavioural therapy (CBT) and the community reinforcement approach (CRA)). Most trials of intensive case management interventions showed a positive effect on reducing substance use, but the effects of the psychological interventions were more mixed (with one trial of CRA showing no significant reduction in illicit drug use).

The authors found that high-risk parent substance misusers (those engaging in a pattern of drinking that leads to the presence of physical or psychological problems, or frequent drug misuse of more than once a month) are most likely to benefit from an ‘extended intervention’^{[footnote 8]} and particularly one in which they are assisted to understand the impact of their actions on their child. Seeking to generate motivation for behaviour change in parents based on the benefits of such a change for their children and family was deemed to increase the chance of success. Overall, however, the authors report that the UK evidence base for individual-focused interventions to reduce parental substance misuse (including both dependent and non-dependent) is weak, relying mainly on small pilot trials.

Individual substance misuse interventions can also result in a decrease in parental conflict, even where this is not a specific objective of the intervention. Rounsaville et al. (2014) report, for example, that successful treatment for alcohol dependence in parents (within four US programmes including inpatient/residential treatment, intensive day treatment and counselling) can lead to a reduction in parental conflict. Their quasi-experimental study shows that children of alcoholics (COAs) were exposed to more parental conflict than the community sample prior to treatment. The exposure significantly decreased between baseline and the six-month follow-up, when their levels of exposure no longer differed greatly to the community sample. The gap widened again at twelve months, but the authors found this to be due to a reduction in parental conflict exposure in the community sample. The authors link the reduced exposure to conflict to their observation of clinically significant decreases in COAs’ ‘emotional mal-adjustment’, when compared to a community sample. The authors use these findings to suggest that interventions should target parental conflict conducted in front of children, and discuss the harmful results with the parents undergoing treatment.

3.3.2 Couples substance misuse interventions

This section outlines the evidence for substance misuse interventions delivered to couples (i.e. both the individual affected by substance misuse and their partner), and the impact of these on substance use as well as relationship conflict.^{[footnote 9]} This evidence is limited by the fact that not all of the studies were focused specifically on a parent population, and so equally did not all assess outcomes for the children of participants, which is an area which may warrant further research. In addition, all studies focused on intact couples.

The most frequently referenced form of substance misuse intervention in the literature with a focus on the couple was behavioural couples therapy (BCT). BCT seeks to directly address the pattern by which substance use and relationship problems can reinforce each other. The intervention aims to make use of the couple relationship as a tool to support the substance abusing partner in their effort to change, and to change the family environment to one which better promotes abstinence (Chanel and Wesley, 2015).

BCT can entail several techniques (see Easton and Crane, 2016 for examples) but tends to begin by encouraging the self-monitoring of use by the partner, as well as identifying the patterns in the relationship which relate to substance use. The non-using partner is taught methods of positive reinforcement to encourage abstinence. Once use has stabilised, the intervention shifts its focus towards the relationship and the building of skills that act to incentivise the affected individual to maintain the change. These include fostering positive feelings towards each other through improving communication, listening and problem-solving skills (Chanel and Wesley, 2015).

A number of studies focused on measuring the impact of BCT interventions on the substance misuse of the affected member of the couple. Strong evidence was found that BCT results in greater reductions in substance misuse than individual behavioural therapy (IBT) (Schumm et al., 2014; Asmussen and Brims, 2018; McCrady et al., 2016b). A randomised control trial (RCT) conducted by Schumm et al. (2014) found that BCT was more effective in improving outcomes for alcohol-dependent women, in terms of abstinence and substance related problems. The study also found a significant interaction between the treatment condition and time, which provided an increasing advantage throughout the follow-up period for women who had undertaken BCT versus IBT on their experience of substance related problems. These same improvements were also seen when both partners were using alcohol, suggesting that involving a substance-abusing partner in BCT (where they are willing) could be beneficial to both parties. Chanel and Wesley (2015) present evidence that while the effects of BCT and individual cognitive behavioural therapy (CBT) were the same at the conclusion of treatment, BCT had a superior effect on the frequency and consequences of substance use after the conclusion. This may suggest that BCT plays a particularly important role in ensuring that any reduction in substance use is maintained long term.

There is some evidence that a blended approach, including both BCT and individual CBT for the affected individual, is even more effective in improving outcomes for substance misuse than alcohol BCT (ABCT) alone. McCrady et al. (2016a) conducted an RCT using an intervention which combined both ABCT and IBT for women with alcohol use disorder, due to reports from women that they preferred individual to couples’ therapy. They found suggestive but still inconclusive evidence that the blended approach supported more positive drinking outcomes than ABCT alone. The blended-ABCT (five sessions of individual CBT and seven sessions of alcohol-focused BCT) had small-to-moderate but non-significant effects on the percentage of drinking days and heavy drinking days during study period, but no overall significant effect on drinking outcomes in the follow-up over ABCT alone. Another RCT conducted by O’Farrell et al. (2017) provided stronger support for the blended approach. Focusing on women using drugs, and in particular opioids, in the US, the study compared those receiving BCT for their drug use with those receiving BCT as well as a separate individual behavioural therapy. Recipients of the combined approach saw more rapid declines of substance-related problems.

Good evidence was also found for the impact of BCT interventions on the relationship satisfaction and functioning of couples in which one or both partners was misusing substances (McCrady et al., 2016b; O’Farrell et al., 2017; Kelley et al., 2016; Chanel and Wesley, 2015; Syed, Gilbert and Wolpert, 2018; Schumm et al., 2014). In an RCT conducted by Schumm et al. (2014), men who had received BCT with their alcoholic partner had significantly higher relationship satisfaction than those whose partner had received IBT only. The authors suggest that these findings should be used to encourage greater participation of men with such initiatives. O’Farrell et al. (2017) also found an improvement in relationship satisfaction for men who received BCT over those whose drug abusing partners received IBT only. However, no similar difference was found for the female drug-abuser in this particular study. This does not necessarily represent a gender effect as only female drug-abusers and their male partners were included in the study’s cohort.

Other studies have found the relationship satisfaction of the partner affected by the substance misuse to improve as well. Schumm et al. (2014) found that the relationship adjustment scores of the women receiving BCT mirrored those of their partners in being higher than those receiving IBT post-treatment, and this gap continued to widen in follow-up. The authors suggest that this may be due to an increasing difference in the substance use problems experienced by those who received BCT versus IBT over the course of the follow-up. The advantage of BCT was also shown to be greater for women who reported a lower baseline relationship satisfaction, perhaps due to their having more room for improvement. Kelley et al. (2016) found that men participating in BCT for their own substance misuse problem reported higher relationship satisfaction at post-intervention, regardless of the number of days abstinent they achieved. The authors suggest that this may be due to the support the men often receive from their partner in accessing the support and in their attempt to recover.

When BCT interventions are delivered to couples who are parents, Syed, Gilbert and Wolpert (2018) present evidence that this can improve the outcomes for their children in relation to emotional and behavioural functioning. This is supported by Kelley, Bravo and Braitman (2017), who found that BCT for alcoholic fathers was associated with an improvement in the child’s wellbeing, reported by the child. A greater number of sessions attended by the affected father was associated with significant decreases in depressive symptoms in the child via increasing relationship satisfaction in both the mother and father (although maternal relationship satisfaction had a more significant effect). No significant indirect effects were found, however, between numbers of sessions and child reported anxiety symptoms through parental relationship satisfaction. The authors suggest that this may be due to their focus on satisfaction, rather than conflict or the perception of threat in the children which has been shown to impact on internalising behavioural outcomes.

In a separate study, Kelley et al. (2016) found that the number of sessions of BCT attended reduces the risk of child abuse indirectly via the impact it has on the relationship satisfaction of the parents. The authors argue that the reduction caused in psychological distress, depressive symptoms, arguing, loneliness and parenting over-reactivity (angering easily or overreacting to a child’s actions) can reduce the risk of child abuse, as all are factors which have been associated with its perpetration (although they do not assess this mechanism in their study). The authors also note that for fathers in particular, relationship satisfaction is related to paternal warmth and closeness towards children.

Syed, Gilbert and Wolpert (2018) suggest that there is a need for a greater number of BCT trials in the UK setting which contain a focus on the long-term outcomes for children, to increase our understanding of this relationship.

3.3.3 Whole family substance misuse interventions

This section reviews the evidence for substance misuse interventions which involve the family of the individual affected by substance misuse, including their children. Studies reviewed assessed the impact of whole-family interventions on substance use of the affected individual, as well as relations within the family (including both interparental and parent-child) and outcomes for the children. These studies were focused on intact families with children.

Daley et al. (2018) divide whole-family interventions for tackling a substance use disorder (SUD) into the following three categories:

• interventions focused on helping the family to influence the member with the SUD to enter treatment

• those which engage family members in treatment with the affected member, in education groups, multi-family groups, individual family or couple’s family sessions

• interventions which help family members to address their own concerns and problems without the affected member engaging in the sessions

This typography illustrates the range of forms that family interventions might take. Sessions may focus on a wide range of issues and skills, for example identifying strategies to improve the motivation to change in the affected individual, improve communication in the family and parental behaviours, reduce conflict between parents and in the family more widely, and increase positive reinforcement of behaviour change (Daley et al., 2018). Templeton (2014) references the importance here of parents being helped to take responsibility for their actions and to understand the impact they have on the children. They argue that families should be helped to talk to each other more openly and respectfully, and the children should be given a voice.

Where interventions engage family members in treatment, it appears that treatment engagement rates are significantly higher, with one study finding 64% to 93% of participants with a substance use disorder engaging compared to 25% who received usual care (Daley et al, 2018).

Whether engagement with family-focused substance misuse treatment improves the effectiveness of treatment in terms of reducing substance use, when compared to individual treatment, is less clear. There is some evidence to suggest that it does. One form of intervention which involves the family in treatment is family psychological therapy. Syed, Gilbert and Wolpert (2018) present evidence from a number of studies (including 5 RCTs, 1 meta-analysis, 3 QEDs and 1 literature review) which show parents who receive family therapy to have significantly lower substance misuse at follow-up, relative to control and alternative interventions including individual counselling. The authors note, however, that most of the RCTs identified were conducted in the US, meaning that UK studies are necessary in order to assess these effects in the UK context.

In terms of the impact of family interventions on the functioning of the family itself, studies utilising a range of methods have illustrated positive outcomes (Templeton, 2014; Syed, Gilbert and Wolpert, 2018; Lewis et al., 2014; Usher and McShane, 2015). A wide range are cited, including improved family functioning, parenting skill, parental warmth, parental emotional regulation, improved family communication (including both interparental and parent-child), cohesion and flexibility, and improved educational and behavioural outcomes for the children. The intensive family preservation service (IFPS), for example, delivered to families in which there are serious child protection concerns relating to parental substance misuse, has been found to deliver consistent improvements in family functioning. UK RCTs are necessary in order to examine the effects in this setting (Syed, Gilbert and Wolpert, 2018; McGovern et al., 2018).

The evidence for the positive impact of other family-focused interventions on family functioning is more mixed. The US-based Strengthening Families programme is a multi-component, 14-session family-skills intervention where children and parents receive individual support, then joint sessions of playtime, communication skills and family planning. Quasi-experimental studies showed the programme to deliver improvements in family functioning, parenting skills and children’s social behaviour, however RCTs did not show the same benefits (Syed, Gilbert and Wolpert, 2018).

In the UK, the Moving Parents and Children Together (M-PACT) programme has been developed based on the US Strengthening Families programme. The programme contains the same focus of improving parent-child relations in families affected by parental substance misuse. A range of child and family-centred approaches are used, including motivational interviewing and cognitive behavioural therapy (CBT), with the aim of developing communication strategies and a ‘toolbox of strategies’ to draw upon in difficult times. Participating families across 13 programmes reported that this resulted in their spending more time together and having stronger relationships. However, these findings are based only on qualitative evidence (Templeton, 2014). While this evidence remains limited, therefore, it does appear that family-based interventions have the potential to generate positive outcomes for the family (Syed, Gilbert and Wolpert, 2018).

There is some evidence to suggest that an improvement in family functioning can, in turn, mediate the reduction of substance use in affected parents. An RCT was conducted to assess the impact of a brief strategic family therapy (BSFT) tackling coexisting parental and adolescent substance use. While the intervention was targeted primarily at the adolescents, it also served to reduce alcohol use in the parents (although the same effects were not seen where the parent was using drugs). While this may partly be explained by the new skills and adaptive behaviours learnt by the parents within the therapy to reduce their substance use, Horigian et al. (2015) argue that the reduction may also be due to the parents experiencing less stress as a result of parent-adolescent conflict, although this was not an explicit aim of the programme.

Parallel parent and child programmes

Some interventions seek to include the whole family, but not necessarily in all of the same activities. For example, the Children’s Program, created in 2010 by a Canadian provider of addiction treatment, offers a four-day intensive programme where children affected by parental substance abuse attend, accompanied by a parent (who may or may not be the parent affected by substance abuse). Parallel groups are run for the child and the parents involving a number of overlapping activities. The programme aims to support children to learn about addiction, develop coping skills and improve their emotional and psychological well-being. The results of a pre-post study of the programme conducted by Usher and McShane (2015) found statistically significant improvements in child emotional and behavioural well-being, as well as parent emotional regulation, parenting and wider family functioning. These interventions are important in attempting to enhance the factors which can protect children from the negative impact of parental substance misuse, which may after all take some time to overcome (Park and Schepp, 2015).

Supporting Kids and Their Environment (SKATE), a programme established in Australia, provided children affected by problematic parental substance use with an eight-week group intervention, delivered at the same time as their parents were receiving drug and alcohol interventions. Joint activities based around play and arts and crafts were also included, such as making family drawings. The pre-post study of the programme conducted by Lewis et al. (2014) found that children showed clinically significant improvement in internalising and externalising behaviours following the intervention (although the reductions were less clear for rule-breaking problems than for aggressive behaviour). The authors suggest that some of these improvements may have been due to the reductions in parent substance abuse which occurred at the same time. The families as a whole also demonstrated improvements in family relationships (although the study did not specify which relationships in particular).

SKATE was developed by family support services, child protection services and drug and alcohol services, as a response to the perceived lack of a co-ordinated response to the complex needs of families dealing with substance abuse. The family support context was seen to be a better context for children and families to receive support for a loved-one’s substance abuse than within drug treatment services. The programme aimed to ensure that where parents were receiving drug and alcohol services, the needs of the children (in terms of coping skills to protect against the risk of poor behavioural outcomes) and issues surrounding wider family functioning were being effectively addressed (Lewis et al., 2014).

The literature also contained discussion of a number of interventions focused only on the child, including school-based programmes, play therapy, social support development activities and group therapy. The Institute of Public Care (2015) states that these programmes can be beneficial for children impacted by parental substance misuse. As one example, an eight-week school-based group programme focused on improving self-esteem and teaching coping strategies to children was found to successfully increase children’s use of positive coping strategies and improve the child’s classroom behaviour, as well as decreasing symptoms of depression (Lewis et al., 2014).

Syed, Gilbert and Wolpert (2018) found more inconsistent results for the school-based interventions they reviewed. Two RCTs of a stress management and alcohol awareness programme involving 6-12 sessions of 1:1 teaching of a resiliency skills-based curriculum found significant improvements in emotion focused coping post-intervention. However, out of four studies assessing school-based support groups and art therapy, only the use of art therapy was found to create significant improvements in coping immediately post-intervention. The evidence is therefore mixed, but it would appear that child-focused interventions at least have the potential to impact positively on the outcomes of dealing with parental substance misuse.

3.3.4 Parenting programmes for parents affected by substance misuse

In section 2 of this report we outlined the combined impact of parental conflict and parental substance misuse on parenting practices, and the risk that poor parenting practices can pose to children (see section 2.5.1). In light of this evidence we concluded that interventions seeking to tackle parental conflict and substance misuse may also wish to consider attempting to improve or consolidate parenting practices. In this section we outline those interventions which provide parenting programmes to parents affected by substance misuse, and present the evidence for the impact of these programmes on both parenting and substance use. Whether study cohorts included both intact and separate or divorced parents was not defined.

There is strong evidence for the impact of parenting interventions for substance misusing parents on their parenting practices and wider family functioning, although this again comes mainly from outside the UK (Syed, Gilbert and Wolpert, 2018; Parliamentary Office of Science and Technology, 2018; Lewis et al., 2014; Horigian et al., 2015). Neger and Prinz (2015) find that where parenting interventions are combined with substance misuse treatment, parenting is improved more than by substance misuse treatment alone. To this they add that parents benefit most when the intervention begins with education in fundamental psychological processes such as emotional regulation mechanisms, before specific parenting techniques are introduced to the programme.

Parents under Pressure (PuP) is one such intervention, which provides a 20-week home-based program to parents receiving treatment for substance misuse, focusing on reducing their potential for child abuse and neglect. Evaluations of the programme (including a UK-based RCT) showed it to have a significant impact on both child and family functioning, including a reduction in child abuse risk, child behavioural problems and parental emotional regulation^{[footnote 10]} (although not in maternal stress) (Lewis et al., 2014; Peisch et al., 2018; Syed, Gilbert and Wolpert, 2018; Barlow et al., 2019). PuP’s substance use module focuses on helping parents to remain abstinent and manage lapses. Where necessary, PuP can also include a ‘relationship module’, which aims to improve communication between parents with a troubled relationship history (Barlow et al., 2019). Unfortunately, the impact of PuP on parental conflict and substance misuse was not assessed in the studies reviewed. Another intervention, Relational Psychotherapy Mother’s Group (RPMG), also decreased the risk of child abuse, but at six-month follow up only the mothers (not children) reported significant differences to the methadone maintenance only group. Two studies found that RPMG improved parent-reported communication and involvement with the child, but not limit setting or autonomy granting, suggesting that the evidence for this intervention is more mixed (Peisch et al., 2018).

There are also examples of behavioural couples therapy (BCT) being combined with parenting interventions. Several RCTs of BCT combined with a 12-week parenting programme called Helping the Non-compliant Child (or the Parent-Child Game in the UK) have shown it to substantially reduce substance use in adults, and also improve outcomes for children (Asmussen and Brims, 2018).

Based on the literature reviewed, however, there is no evidence of parenting interventions combined with substance misuse treatment having an impact on the substance misuse of the affected parent, over and above treatment as usual. However, there is some evidence that brief parenting skills interventions delivered in primary care can successfully encourage affected parents to enter substance misuse treatment (Syed, Gilbert and Wolpert, 2018).

3.3.5 Domestic abuse and substance misuse interventions

Due to the prevalence of co-occurring substance misuse and domestic abuse, a number of interventions exist which seek explicitly to tackle both simultaneously^{[footnote 11]}. There is promising evidence that this blended approach creates a more significant reduction in substance misuse than substance misuse interventions alone, and that it may also reduce domestic abuse. Whether this advantage is sustained in the longer term, however is less clear (Wilson, Graham and Taft, 2014; Chermack et al., 2015; Easton, Crane and Mandel, 2017).

Easton, Crane and Mandel (2017) describe an integrated substance use and domestic abuse therapy that uses cognitive behavioural therapy (CBT) skills training to target substance use, aggressive behaviour and the interrelationship of the two. These therapies contain an emphasis on anger management, good communication and conflict resolution skills training. The authors suggest that there is good evidence for the effectiveness of these interventions in reducing both substance misuse and violence. They present evidence from one RCT which showed participants in the combined intervention to have significantly fewer episodes of DA in the follow-up period, which they attribute in part to a reduction in substance use. They also suggest that these therapies can disrupt the association between alcohol use and DA, as those receiving the therapy were less likely to be violent on drinking days than the control group. The authors note, however, that these are early findings which require further research.

Easton and Crane (2016) report that referring perpetrators of domestic abuse to separate treatment facilities to address the DA and another behaviour disorder such as addiction, is an ineffective method. They suggest that this means care is not co-ordinated, as agencies do not communicate and have too high a caseload. They also report evidence that the motivation of a perpetrator to engage with support may decrease (from an already low baseline), if they are required to go to two locations.

The partner is not required to be involved in the combined intervention, but other approaches use interventions delivered to the couple. Behavioural couples therapy (BCT) can be used for couples engaged in violent conflict, and there is some evidence of this reducing substance use and violence when couples are willing to engage (McCrady et al., 2016b). Another study found that multi-couple group therapy was more effective than individual couple therapy in increasing relationship satisfaction and reducing relationship aggression (Easton, Crane and Mandel, 2017). Wilson, Graham and Taft (2014), report that overall the evidence for couple interventions to tackle substance misuse and violence is weak.

3.3.6 Substance misuse interventions delivered through the criminal justice system

Family drug and alcohol courts (FDACs) are the only evaluated court-based system of support for families affected by parental substance misuse internationally (Syed. Gilbert and Wolport, 2018). This section outlines the evidence for the impact of FDACs on parental substance use as well as child outcomes.

FDACs have existed in the UK since 2008. The model for an FDAC is that a judge is responsible for adjudicating the care proceedings for the child in a family affected by substance misuse, but is also responsible for running a specialist treatment court in which they aim to motivate parents to change and remind them of their responsibilities, with the aim of reunifying the family. A specialist multi-disciplinary team is attached to the court to deliver an intervention plan for parents. Parents are supported in fortnightly problem-solving therapeutic reviews, which involve the parents, the judge, social workers and parent mentors.

There is promising evidence from UK trials to suggest that FDACs are effective in increasing parental engagement with the recovery process, increasing abstinence (measured by drug tests) and improving reunification rates (Asmussen and Brims, 2018; McGovern et al., 2018; Ward, Brown and Hyde-Dryden, 2014). One study of a UK pilot showed that the inclusion of a timely and co-ordinated package of interventions from a range of professionals was necessary for the success of FDACs (Ward, Brown and Hyde-Dryden, 2014). The long-term outcomes of the use of the courts for the children involved, however, remains unclear (Asmussen and Brims, 2018; McGovern et al., 2018). In addition, no RCTs have yet been conducted in the UK, meaning that larger and more robust evaluations are required in the UK context (Syed, Gilbert and Wolpert, 2018).

3.3.7 Parental relationship interventions

While the focus of this chapter is primarily on substance misuse interventions which also impact upon parental conflict and parenting practices, a number of interventions focused specifically on the parental relationship were also identified in the literature.

None of the studies on interventions aimed at improving parental relationships examined their impact on substance misuse. That said, these studies may contain lessons applicable to any initiatives attempting to tackle coexisting parental conflict and substance misuse. For an examination of the effectiveness of parental relationship interventions, please see Harold et al. (2016).

3.4 How interventions create impact

In this section we review how the successful interventions described in section 3.3 come to support a reduction in parental conflict and substance use. These findings have been taken from a range of interventions, but with a particular focus on those which are aimed at tackling substance misuse and which, in turn, have a positive impact on parental conflict and wider family functioning. The three main mechanisms by which these interventions impact upon parents and families are:

• parents taking more responsibility for their actions

• improved communication in the family (both interparental and parent-child)

• skill-building in the family

These can, in turn, lead to longer term improvements in family functioning, relationships and relationship satisfaction, and contribute both to a reduction in parental conflict and in substance misuse.

3.4.1 Parents taking more responsibility

Successful interventions frequently focus on supporting parents to take responsibility for their actions and increase their understanding of the impact that their actions can have on their families, relationships, and the outcomes of their children. This can apply equally to the impact of a parent’s substance misuse, parental conflict, or both. Taking responsibility in this way can help to build the motivation of parents to improve the quality of their relationships (both inter-parental and parent child) and/or reduce their use of substances, through continuing to engage with interventions and maintain any changes made. These findings were drawn from literature reviews and a primary qualitative study (Templeton, 2014; McGovern et al., 2018; Harold et al., 2016).

One such example is the M-PACT programme in the UK, which sought to tackle addiction in parents as well as wider family functioning and conflict. The programme successfully provided parents with a better understanding of their addiction and how it affects children and family members, and children were also helped to see that their parents’ addiction was not their fault. The result of this was that children reported taking on less responsibility at home and having more time to be children (Templeton, 2014). It should be noted, however, that there is only qualitative evidence to support this finding and as such there is still no evidence to prove that the programme is effective in this regard.

3.4.2 Improving communication

Studies showed that improving communication is an important factor in improving family functioning and reducing parental conflict. This evidence was drawn from studies utilising a range of methods (Lewis et al., 2014; Templeton, 2014; McCrady et al., 2016a). As outlined in the first chapter of this report, effective family functioning and harmonious parental relations can act as a protective factor for children affected by parental substance misuse, reducing the risk of their experiencing adverse outcomes.

An important element of the BCT interventions discussed in section 3.3.2 is improving communication between the couple, in order to foster more positive relations between them. This, in turn, was seen to motivate both the affected partner to maintain abstinence, and the non-affected partner to maintain their support and positively reinforce changes made (Chanel and Welsey, 2015; McCrady et al., 2016a).

With regard to family functioning more widely, quasi-experimental studies have shown the US-based Strengthening Families Programme (SFP) to be effective in improving family functioning, parenting skills and children’s social behaviour. The programme’s primary input is communication training. The UK M-PACT programme (derived from SFP) is again seen as a successful example here. The programme facilitated participating families to talk openly about addiction and to communicate calmly. The result was that both parents and children reported that they had learned to listen to each other, communicate more effectively and be more respectful of each other. Many families reported a reduced number of arguments and conflict throughout the course of the programme (Templeton, 2014).

Separately, the Parents Under Pressure Programme, aimed at preventing child neglect in substance misusing parents, successfully fostered new patterns of communication between parents and children through discussion of family events and issues (Lewis et al., 2014). Evaluations (including a recent RCT conducted in the UK) have shown this programme to significantly improve family functioning, including child abuse risk and child behavioural problems (Lewis et al., 2014; Barlow et al., 2019).

3.4.3 Skill-building

Harold et al. (2016) found that where skill-training is included in a programme to tackle parental conflict, greater benefits in couple communication and problem-solving are achieved.

Skills-training focused on emotional coping strategies can also help parents to manage the triggers to substance use, serving to support a reduction in this as well. Neger and Prinz (2015) suggest that these skills can also better equip parents to respond to and improve the child behaviour problems and issues that commonly co-occur with parental substance misuse.

An integrated intervention for men affected by substance misuse with a history of domestic abuse, employed cognitive behavioural therapy (CBT) skills training in order to tackle the substance misuse and aggressive behaviour and the interrelationship of the two (Easton, Crane and Mandel, 2017)

For the children affected by parental substance misuse, it is important for interventions to provide them with coping skills which can improve their adaptive response to the stressors they are experiencing, thereby protecting them from negative outcomes (Lewis et al., 2014; Institute of public care, 2015).

These findings, drawn primarily from literature reviews, suggest that there may be a set of skills which when focused on within an intervention can help to improve outcomes across all four key domains: substance use, parental conflict, parenting practices and child development.

3.5 Measuring the impact of interventions

This chapter has reviewed a broad range of interventions which have in turn sought to attain a broad range of outcomes. These can be divided into the following five major subsets:

• substance use outcomes

• relationship outcomes

• parenting outcomes

• domestic abuse outcomes

• outcomes for children

Within each of these themes, a wide range of outcome measures were used by the studies reviewed. The most frequently reported are listed in the following sections. The measures included are not necessarily recommended for use, as the validity of these measures have not been assessed as part of this literature review.

3.5.1 Substance use outcomes

The primary intended outcome for many of the interventions reviewed in this chapter was a reduction or an end to the substance misuse of the affected parent. The studies used various tools to measure substance misuse and thus evaluate the impact of the programmes. These include the following:

• TimeLine Follow Back (TLFB) tool, makes use of a calendar and memory prompts to facilitate tracking and recall of substance use (Stover, 2015; Chermack et al., 2015; Horigan et al., 2015)

• the substance abuse-dependence module of the computerised C-Diagnostic Interview schedule for Children (DISC-SAA) (Horigan et al., 2015)

• Alcohol Use Questionnaire and Screening Questionnaires T-ACE and TWEAK, used to help assess the extent of alcohol use and the risk posed to child welfare (Institute of Public Care, 2015)

• alcohol and drug use items from the Addiction Severity Index-Lite, a standardised semi-structured interview used to ascertain self-reported lifetime and current substance use status (Horigan et al., 2015)

• Alcohol Use Disorder Identification Test (AUDIT) and the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) (McGovern et al., 2018)

• Alcohol Use Disorder and Associated Disabilities Interview Schedule (AUDADIS), used to assess history of substance misuse as well as family history of depression (Alonzo et al., 2014)

• self-reported measures were sometimes used alongside biological analyses such as random urine or hair toxicology screens, the combination of which can improve validity (Neger and Prinz, 2015)

3.5.2 Relationship outcomes

For those interventions tackling substance misuse alongside parental conflict, a secondary intended outcome was a reduction in parental conflict and improvement in relationship quality. Studies made use of a variety of scales and measures to measure these outcomes.^{[footnote 12]} These include the following:

• five-point Likert scale measuring frequency of arguments among parents (McLaughlin et al., 2015)

• six-item subscale used to assess marital relationship quality of parents from the perspective of the child, based on how often they get along well together, agree on rules about their child, engage in arguments, hesitate to talk about on parent in front of the other, or how often the youth feels caught in the middle of their parent’s interaction (Jennison, 2014)

• Family Environment Scale (FES), otherwise known as the Cohesion and Conflict scale (Horigan et al., 2015)

3.5.3 Parenting outcomes

Various measures were used within the literature to assess parenting outcomes. A systematic review conducted by Neger and Prinz (2015) noted that in the 21 studies reviewed related to parenting and substance misuse, the measures varied widely and ranged from those focusing on parenting style or practices, to those reflecting broader constructs which include parenting (for example the Parenting Stress Index or Child Abuse Potential Inventor).

The measures cited in the literature include the following:

• the co-parenting relationship scale, a comprehensive self-report measure (Stover, 2015)

• the Parenting Scale, a self-report measure (Neger and Prinz, 2015)

• the Child Interactive Behaviour Rating, a scale used to rate parent and child interaction during video recorded session, used widely and includes good construct validity, predictive validity of child adjustment and 2-year test reliability (Stover, 2015)

• the Parenting Practices Questionnaire from the Chicago Youth Development Study (Horigan et al., 2015)

• family adaptability and cohesion evaluations scales version IV (Usher and McShane, 2015)

3.5.4 Domestic abuse outcomes

For those interventions which focus on achieving a reduction in domestic abuse, the following measures have been used to evaluate success in the studies reviewed:

• the TimeLine Follow Back Spousal Violence, used to identify specific days of interpersonal conflict at various intervals (Stover, 2015; Chermack et al., 2015)

• the Revise Conflict Tactics Scale (Stover, 2015)

3.5.5 Children’s outcomes

A limitation of the studies reviewed for this chapter was that few contained a direct focus on the impact of the intervention on the outcomes for children. There is a clear need for a stronger evidence base of UK trials to establish what works for children (Sellers, 2016). Those that did discuss outcomes for children did not often make use of quantifiable measures. As yet there are not well-established measures used to evaluate the impact on children of programmes tackling parental conflict and/or substance misuse (Callanan et al., 2017). Those metrics that were cited in the literature include the following:

• the Diagnostic Interview Schedule for Children-Predictive Scales (DISC-PS), used to assess anxiety and depressive symptoms, and to identify the presence of a number of other psychological issues

• the Strengths and Difficulties Questionnaire, an emotional and behavioural screening tool for children (Horigan et al., 2015). Usher and McShane (2015) report, however, that this is not an adequate measure

• the Mood and Feelings Questionnaire, a screening tool and measure of depression in children (Usher and McShane, 2015)

• the Child Depression Inventory (CDI), a 10-item self-report instrument used to assess depressive symptoms in the last two weeks (Kelley, Bravo and Braitman, 2017)

• the Revised Children’s Manifest Anxiety Scale (RCMAS), a self-report instrument to assess anxiety symptoms (Kelley, Bravo and Braitman, 2017)

3.6 Challenges in measuring impact

There are a number of challenges in measuring the success of any programme, but particularly those which are attempting to tackling potentially long-entrenched and complex programmes in a long-term timeframe. Callahan et al. (2017) identify the following challenges in measuring the outcomes of relationship services, which are largely also applicable to those interventions tackling substance misuse or substance misuse and parental conflict combined:

• difficulty in capturing change over time, requires identification of a clear start and end point, as well as consistency in data collection over the period

• non-responses from participants

• difficulty in attributing change to the intervention as opposed to other interventions received or wider contextual factors

• difficulty in capturing long term outcomes beyond the time-scale of the intervention’s delivery

• difficulty in measuring the prevention of developing need

Despite these challenges, a greater number of rigorous evaluations of interventions and their effectiveness in the UK are required, to build the evidence base surrounding what works in tackling these issue areas (Velleman and Templeton, 2016).

3.7 Gaps in the evidence

This section presents a summary of the gaps in the evidence identified in sections 3.3 to 3.6.

• interventions delivered to the couple: only a small number of the studies examining interventions delivered to the couple were focused specifically on a parent population. In addition, the studies identified focused on intact, heterosexual couples

• interventions delivered to the family: while the review identified some evidence that the involvement of the whole family in substance misuse treatment can increase engagement rates and improve substance use outcomes, there was a lack of evidence regarding what form of family involvement is most effective

• evaluation: in general, there is a need for larger and more robust evaluations of interventions to tackle substance misuse and/or parental conflict in the UK context

• child outcomes: few of the studies reviewed contained a direct focus on the impact of the intervention on the outcomes for children. Those that did discuss outcomes for children rarely made use of quantifiable measures

4. Characteristics of effective practice

4.1 Overview

While successful interventions take many forms, and there are no definitive rules for ‘what works’, our review highlighted a number of considerations and common themes relating to design and delivery which influence the effectiveness of interventions. These features include the following:

• intervention timing and sequencing

• engagement and retention of participants

• socio-demographic characteristics of participants

• intensity of intervention

• format of intervention

• technique or therapy deployed

• multi-agency working

As in previous sections, our evidence base is focused primarily on those interventions which are explicitly aimed at tackling substance misuse and which, in turn, have a positive impact on parental conflict and wider family functioning. Where possible, we have also drawn parallels with interventions focused solely on parental conflict.

4.2 Key findings

Intervention timing and sequencing

• There is consistent evidence that early intervention is important in preventing adverse outcomes for children affected by both parental substance misuse and conflict.

• There is consistent evidence that tackling parental substance misuse and parental conflict/parenting within an integrated intervention is an effective approach. It may, however, be necessary within such an intervention to focus on stabilising substance use before directly addressing additional components.

Engagement and retention

• Common barriers to accessing both substance misuse and parental conflict interventions include: a lack of recognition of the problem or motivation to change; stigma surrounding substance misuse and/or conflict and receiving help from statutory services and; difficulty accessing support due to its location, timing, the need for childcare or cost.

• There is evidence that where interventions provided parents with food, transportation vouchers and child care during sessions, or delivered sessions in the participant’s home, participation and retention rates increased.

Sociodemographic characteristics of target group

• Interventions may need to be tailored if they are to engage with and work effectively for participants of different age, gender, ethnicity and socio-economic status.

• The literature lacked conclusive evidence about how best to engage and support these various groups, particularly LGBTQ+ couples and divorced or separated couples.

Intensity and length of intervention

• There is consistent evidence for the positive impact of intensive case management (ICM) on substance use of participants and wider family functioning. Evidence is more mixed for the impact on child outcomes.

• There is some qualitative evidence that a long-term relationship with a key worker can be beneficial in motivating sustained engagement with an intervention.

• There is some evidence that a more extended intervention is more effective for high-risk substance misusers and those in greater relationship distress.

• There is mixed evidence for the effectiveness of brief substance misuse interventions.

Format of intervention

• Interventions should consider which intervention format is most appropriate for their target population and priorities.

• There is, for example, some promising evidence that group-based interventions involving multiple families can be beneficial for the children and families of those affected by substance misuse.

Techniques employed

• Various techniques and therapies can be used successfully within substance misuse interventions, and interventions should consider which combination they should employ.

• There is, for example, some evidence that motivational interviewing can increase subsequent retention in substance misuse interventions when combined with BCT.

Multi-agency working

• Multi-agency working can help to ensure that the full range of needs for the individual and the family are addressed and that support is co-ordinated.

Gaps in the evidence

The review encountered the following gaps in the evidence base:

• Interventions targeting non-dependent substance misuse.

• The impact of various sociodemographic characteristics, including socio-economic status, sexuality and whether a couple is intact or separated/divorced, on access, retention and outcomes for participants in substance misuse interventions.

Future research should attempt to isolate the particular element(s) of an intervention’s format or content which make it successful.

4.3 Intervention timing and sequencing

4.3.1 Timing

For those interventions aimed primarily at reducing parental substance misuse, research suggests that early intervention is essential. In particular, early intervention is deemed necessary to address any potential adverse impact on affected children and prevent long-term harm and child protection issues from developing (McGovern et al., 2017; Laslett et al., 2015). For the same reason, McGovern et al. (2018) suggest that while the majority of substance misuse interventions target dependent users, there should be a greater focus on non-dependent but high-risk users.

Some studies also suggest the same need for early intervention in relation to parental conflict (e.g. Doubell, Stock and Acquah, 2017). The EIF suggests targeting interventions at points of transition known to be potentially stressful, for example marriage, parenthood, separation, children entering school, or times at which families are at risk of poverty due to unexpected unemployment or health problems (Doubell, Stock and Acquah, 2017).

On the other hand, there is some evidence to suggest that support offered at times when the family is tackling a lot of other issues (and so is at increased risk of initiating parental conflict) can reduce intervention uptake, as families do not have the available capacity to engage (Callanan et al., 2017). This might suggest that delivering interventions immediately prior to predicted stressful life events could be most effective, however the literature contained no evidence to support this notion. Connected to this, where an intervention is seeking to tackle two or more issues in a family’s life, there is a question around whether various elements of an intervention should be delivered simultaneously or in a staggered format.

4.3.2 Sequencing

Where an intervention is seeking to tackle more than one issue, for example both substance misuse and parental conflict, a question arises around the sequencing or combination of these different components. For the tackling of both parental conflict and substance misuse, the most commonly used intervention is BCT. The design of BCT interventions ensures that both conflict and substance misuse are addressed simultaneously within the intervention, with the aim of overcoming the mutually-reinforcing patterns that exist in the couple’s interactions and the substance misuse of one or both partners. BCT aims to tackle both problems at once, as improved communication and behaviours in the relationship can aid and reinforce the process of reducing substance use in the affected partner. Having said this, while the couple is the focus throughout, interventions tend to begin by stabilising or reducing substance misuse in the affected individual, before then moving on to strategies and skills focused on the relationship more broadly (Chanel and Wesley, 2015).

Neger and Prinz (2015), in their systematic review of interventions related to both parenting and substance abuse, find some evidence to suggest that participating in both substance misuse treatment and parenting interventions simultaneously maximises efficiency, and takes advantage of the engagement of parents in the substance misuse treatment to tackle the secondary but highly important issue of parenting. This principle may also apply to interventions seeking to tackle both parental substance misuse and conflict, but no evidence for this suggestion was presented within the literature.

Some studies of parenting programmes, however, suggest that attempting to address issues surrounding parenting and the parent-child relationship before meaningful progress has been made in the substance misuse treatment and in addressing the parents’ own psychological needs, is not productive. There is also some evidence to suggest that delaying the parenting content in the programme increases treatment retention rates compared to interventions which provided the parenting content immediately (Neger and Prinz, 2015).

Taken together, this evidence suggests that seeking to tackle parental substance misuse and parental conflict/parenting simultaneously within an integrated intervention is an effective approach. Within an integrated intervention, however, it appears that it may be necessary to stabilise substance use before directly addressing the additional components.

4.4 Engagement and retention

4.4.1 Barriers to engagement and retention

Across interventions for both parental conflict and substance use, the main barriers to engagement and retention of support are similar. These are namely:

• awareness and motivation: a lack of recognition or acceptance that there is a problem, or a lack of motivation to change

• stigma: stigma surrounding substance misuse and/or parental conflict and also around receiving help from statutory services

• accessing support: inconvenient location and timing of support, the need for childcare and the cost of accessing support

Any successful intervention will have to consider how best to overcome these various barriers (Pote et al., 2019; Asmussen and Brims, 2018).

Awareness and motivation

A systematic review conducted by Asmussen and Brims (2018) points to the problem of parental resistance to substance misuse interventions as a major primary barrier to engagement. Parents may be in denial about the extent of their problem, or they may be ambivalent about changing it. This is supported by Daley et al. (2018) who find that a lack of awareness of the substance use disorder in the affected individual, as well as low motivation to accept help, can contribute to low treatment take-up. Co-morbid mental health problems may also reduce engagement and retention within programmes (Braitman and Kelley, 2016).

A similar set of issues appear in relation to engagement with parental conflict programmes. The EIF lists barriers including denial or failure to recognise the severity of relationship problems, meaning that support is often only sought when crisis point has been reached (Doubell, Stock and Acquah, 2017). Parents are also often unaware of the relationship support available to them (Pote et al., 2019).

When the issue is one of substance dependence, Daley et al. (2018) also make the point that the addiction in itself and the power it holds over the individual acts as a powerful barrier. Another study found that many patients dropped out of a BCT drug-treatment service quickly and went back to using, before they could be engaged in the treatment. This was found to be particularly likely where both members of the couple were using drugs (O’Farrell et al., 2017).

Stigma

The stigma surrounding substance misuse problems was reported by one study to be a major factor discouraging parents from seeking help from professionals, as well as sometimes those outside the immediate family, due to a feeling of shame. The study also cites fears surrounding the potential child protection implications of receiving help with substance misuse as an important barrier to engagement. These fears can lead to a vicious cycle in families where the pressure to maintain secrecy may lead to increased substance misuse in order to cope. Existing mental health issues may also be exacerbated by the fear of stigma and the secrecy. Children are also more likely to experience negative outcomes in such a climate, as they may feel unable to talk to anyone about their experiences (Ward, Brown and Hyde-Dryden, 2014).

Stigma can also act as a barrier to engagement with parental conflict programmes. In particular, seeking help from statutory services for parental conflict can be resisted due to the association with social care and the removal of children (Doubell, Stock and Acquah, 2017; Pote et al., 2019). Relationship problems may also be seen as a private matter in which external involvement is unwelcome (Pote et al., 2019).

Accessing support

One US study showed that many parents who reported substance misuse treatment failures pointed to childcare concerns, as well as the need to balance the demands placed on them by substance misuse treatments with those of the child protection service, as the main reasons for their failure to engage with a programme (Neger and Prinz, 2015).

Again, the parental conflict literature presents a similar picture. A lack of childcare support, a lack of co-ordination of services meaning that they are difficult to find, having to travel long distances (particularly in rural areas) and interventions occurring during the working day are all barriers to engagement with parental conflict programmes (Doubell, Stock and Acquah, 2017; Pote et al., 2019).

Interventions that require a fee for participation will act as a barrier to engagement for those less able to pay for parental conflict programmes (Pote et al., 2019). This issue was not explicitly addressed in the substance misuse literature, but the same appears likely to apply. Even where fees do not apply, those less able to pay for childcare and transport are likely to face greater barriers to access.

4.4.2 Enablers of engagement and retention

Awareness and motivation

A lack of awareness in parents that they have a problem with parental conflict and/or substance misuse and should seek help, or a reluctance to do so, are difficult barriers to address within the design of an intervention itself. Timing may come into play here, however, as qualitative studies have found parents to be more open to support at key transition points such as the birth of a first child, when they are motivated to ‘get things right’ (Pote et al., 2019).

With regard to substance misuse treatment, evidence from one literature review suggests that where individuals were under a mandate or pressure from the legal system, an employer or the family, they were more likely to enter substance misuse treatment, suggesting that external pressure may be important in motivating individuals or persuading them that they need help (Daley et al., 2018). Connected to this, another qualitative study highlighted how some families were motivated to engage in substance misuse programmes by opportunities to increase contact with their children or having their children returned (Templeton, 2014).

Stigma

One suggestion in the parental conflict literature, based on qualitative studies conducted with both service users and practitioners, was that offering relationship support within universal family services could reduce the associated stigma (Pote et al., 2019; Callanan et al., 2017). No evidence for ways in which interventions had attempted to reduce stigma was found in the substance misuse literature.

Accessing support

One study found that substance misuse interventions providing parents with food, transportation vouchers and childcare during the sessions reported significantly higher retention rates (Neger and Prinz, 2015). Similarly, the EIF recommend that parental conflict interventions should be delivered at convenient and flexible times and locations, and that an offer of free or subsidised support should be considered (Pote et al., 2019; Callanan et al., 2017).

Another factor which appears to impact on motivation to engage with treatment is the treatment setting itself. Neger and Prinz (2015) suggest that although inpatient treatment facilities for substance misuse might be expected to result in better retention rates for parents due to the provision of a secure living environment and the ability to focus on recovery while care for their children is provided, this appears not to be the case. Instead, the authors found that retention rates were just as good in outpatient settings. Overall, they found that the setting which produced the highest retention rates was the home environment, as this avoided the parents having to arrange transportation or childcare to attend outpatient setting, and also avoided their having to give up independence to receive residential treatment.

There is some evidence in the parental conflict literature to suggest that self-directed interventions in the home environment, such as an online course, can help to engage groups facing particularly high access barriers in parenting and parental conflict interventions (Pote et al., 2019; Callanan et al., 2017). This idea was not discussed in the substance misuse literature, however, and may well be less suitable.

4.5 Sociodemographic characteristics

Studies suggest that interventions have differential success at engaging, retaining and helping individuals and families depending on different socio-demographic factors (in particular, age, gender, culture and ethnicity). If it is to succeed, therefore, the design of an intervention must consider its target group(s) and how best to facilitate positive engagement with the programme. More research is required to increase our understanding of how to do this.

Within the substance misuse literature there was a lack of evidence regarding the engagement of LGBTQ+ parents and couples, or different family structures. There was no evidence in the literature regarding the engagement of separated or divorced parents and couples within interventions, as all the substance misuse interventions identified in the studies reviewed were targeted at intact couples and families (or otherwise the target group was not explicitly specified). In addition, studies did not discuss the engagement or effectiveness of interventions for married couples compared to cohabiting couples. For a discussion of engaging these groups and others within parental conflict interventions please see Pote et al. (2019).

4.5.1 Age of parent

One study conducted by Braitman and Kelley (2016) into engagement with couples’ therapy for substance misuse has shown that services are more successful at starting treatment with women who are older when they first think that they have a problem. While the sample size of this study is small, this finding appears to be in line with previous research. The authors explain this by suggesting that services are more effective at engaging with older women who may have fewer issues to overcome in terms of childcare and transport.

For men, it appears that those experiencing drug misuse or both drug and alcohol misuse are less likely to begin treatment than women if they are older, but that men diagnosed with an alcohol disorder were increasingly likely to engage with age (Braitman and Kelley, 2016). Further, Pote et al. (2019) highlight that young parents are harder to engage in interventions designed to improve parenting skills and reduce parental conflict. They report that this is particularly true of young parents facing other adversities such as low income and unstable housing (Pote et al., 2019).

4.5.2 Age of children

Findings from parenting interventions (without a focus on parents affected by substance misuse) suggest that tailoring the intervention to focus on a parent’s immediate needs based on their children’s ages may have the greatest immediate impact. Neger and Prinz (2015) argue, however, that focusing only on a small age-range may leave parents without comparable knowledge of what to do as their children grow up. These principles may well be transferable to any inclusion of parenting skills training within an intervention focused on substance misuse and/or parental conflict.

4.5.3 Gender

A review study conducted by McGovern et al. (2018) found that mothers involved in initial trials of FDACs were significantly more successful at engaging and training mothers in treatment than fathers. FDACs were also more likely to be successful at ‘graduating’ women from the drug court and reunifying them with their children. This suggests that services find it easier to engage mothers in substance misuse interventions than fathers, particularly when the future of their children is at stake. Similarly, evidence from the parental conflict literature shows that men are harder to engage in parental conflict and parenting interventions than women, due to a greater reluctance to seek help. These findings support wider evidence which shows that men are less likely to seek support for physical and mental health problems (Pote et al., 2019).

That said, some interventions have difficulty in engaging women. Studies have shown that some services find it difficult to engage women with alcohol use disorder in behavioural couples therapy, as they tend to prefer individual therapy (McCrady et al., 2016; Braitman and Kelley, 2016). One mixed methods study found that when offered the choice between couples and individual therapy, women disproportionately selected the latter, reporting reasons including that they would prefer to work on problems individually, a lack of support from their partner, and the logistics of scheduling joint sessions. Another similar study found that women who chose couples treatment were significantly less likely to actually begin the treatment, and those assigned to couples’ treatment missed significantly more sessions than those in individual treatment. It is for this reason that McCrady et al. (2016) conducted an RCT of a combined offer of BCT and individual cognitive behavioural therapy for women with alcohol use disorders (Blended-ABCT), which was shown to deliver similar or slightly better outcomes than BCT alone.

Research has also shown that services are more successful at encouraging couples to enter treatment for substance misuse if the male partner has a higher level of relationship satisfaction at baseline. One explanation for this is that women on the whole appear to be more supportive of their male partner’s decision to enter treatment, which may encourage the male partner to comply if his relationship satisfaction is higher (and may also then be part of the reason for a further increase in relationship satisfaction post-intervention). For women affected by substance misuse, however, greater reported relationship cohesion was associated with lower initiation of treatment. This may be because women in more cohesive relationships perceive their substance misuse to be less of a problem (Braitman and Kelley, 2016).

4.5.4 Culture and ethnicity

Studies state the need for interventions tackling parental conflict and/or substance use to take into account cultural differences in their target group. This is particularly important because levels of engagement among ethnic minority groups are often low (McCrady et al., 2016b; Neger and Prinz, 2015; Callanan et al., 2017). McCrady et al. (2016b) point out that different cultures have different customs and expectations around drinking and drug-taking, parenting and relationships, as well as the seeking of help from professionals for problems more generally. The authors also note the importance of understanding patterns of communication used in different cultures. BCT, for example, is focused on shaping patterns of communication and couples-based problem solving, but this may need to be tailored to be suitable for a variety of cultures.

4.5.5 Socio-economic status

As noted in section 4.4.1, many barriers to accessing services can be felt more acutely by parents with a low socio-economic status (SES), due to the cost of travel, childcare and sometimes the interventions themselves. The impact of SES on access, retention and outcomes for participants in substance misuse interventions was not directly addressed in the literature reviewed, and so may be an area which could benefit from further research.

A literature review conducted by the EIF shows families of low SES to be less likely to initiate, engage with and complete parenting and parental conflict programmes than families of high SES. The study suggests that this may be due in part to the other stressors that families with low SES are likely to experience, which may reduce capacity to engage with programmes. As noted in section 2.7 both relationship difficulties and substance misuse can often coexist with and be exacerbated by these stressors, such as a lack of economic resources, unstable jobs and unsafe neighbourhoods. The EIF report makes the case that these families may require support with these other issues, if they are to have the capacity to focus on relationships (Pote et al., 2019). It would appear that the same logic can be applied to substance use. In addition, a qualitative study has identified the need for extra support to be offered to participants in poverty, if programmes are to be successful in engaging this group (Callanan et al., 2017).

4.6 Intensity and length of intervention

There is good evidence that the use of intensive case management (ICM) can achieve good outcomes across a range of the interventions reviewed in section 3.3, especially those focused on substance misuse. ICM means that care and support is delivered by one team with a fairly small caseload, often over an extended period. Access to treatment services is co-ordinated by the team and often facilitated through the provision of transport or onsite services and childcare. McGovern et al. (2018) present evidence that treatment delivered to individual parents to reduce dependent or non-dependent substance misuse was more effective when delivered through intensive co-ordination and case management, increasing the number of services a parent engaged with and increasing rates of successful completion. The authors find the same for substance misuse interventions which include the entire family, reporting that ICM significantly reduced drug and alcohol misuse.

Intensive family preservation programmes (IFPP) are targeted at families experiencing high risk substance misuse and family functioning issues, who are deemed to be ‘in crisis’ or close to the child being taken into care. Services are flexible and available to families 24 hours a day for a period of four weeks (Ward, Brown and Hyde-Dryden, 2014). There is promising evidence that families offered IFPPs make improvements in family functioning and reduce or stop taking drugs (Syed, Gilbert and Wolpert, 2018; McGovern et al., 2018).

McGovern et al. (2018) also present evidence about trials of the FDAC in the UK, and report that decreased substance misuse was found to be associated with the ICM intervention provided through the court.

The impact on the child of the use of ICM in interventions for the parent or family appears less clear. One quasi-experimental trial of IFPP in the UK saw fewer children enter care or reach permanency, although this was based on a small sample size (McGovern et al., 2018). Another study, however, found no evidence of a reduction in out of home placements (Syed, Gilbert and Wolpert, 2018). Ward, Brown and Hyde-Dryden (2014) suggested that the IFPP may not be long enough in duration to help families to address the complex problems sufficiently to prevent their child entering care.

One of the pay-offs of more intensive working appears to be the development of a trusted relationship between the affected individual or family and a key worker, which can assist to motivate sustained engagement with an intervention (Institute of Public Care, 2015). For male children in particular, one study made reference to the particular importance of male key workers, and the impact that they can have on children whose father may be misusing substances (Templeton, 2014).

At the other end of the spectrum are brief interventions (e.g. primary care assessments, psycho-education sessions). These vary in content and length, but usually entail a process of screening or assessment, a brief intervention (ranging from a short advice session to counselling from a trained practitioner) and then referral to specialist treatment if required (Syed, Gilbert and Wolpert, 2018). The evidence for the efficacy of brief interventions in reducing harmful substance misuse is mixed (Syed, Gilbert and Wolpert, 2018; Asmussen and Brims, 2018). The Cochrane Review of alcohol brief interventions found moderate evidence that brief interventions can reduce alcohol consumption compared to minimal or no intervention, and reports that ‘longer counselling duration probably has little additional effect’ (Kaner et al., 2018). A systematic review conducted by Asmussen and Brims (2018), on the other hand, reports that despite some early positive findings, recent trials have found brief interventions to have no lasting effect on the drinking behaviours of adults and have failed to prevent relapse.

Where brief interventions may be more promising is in those initiatives offering brief psycho-educational and parenting skills sessions prior to substance misuse treatment programmes, to encourage engagement. There is some evidence that parents participating in these interventions may be encouraged to enter treatment, and that the psychosocial functioning of family members may also be improved (Syed, Gilbert and Wolpert, 2018). Separately, McCrady et al (2016b) report that a one-session brief family intervention (BFT) involving the individual affected by substance misuse and a partner or parent, can encourage subsequent treatment engagement for men affected by substance misuse over treatment as usual.

With regard to the length of intervention, studies have shown that couples engaged in alcohol-focused behavioural couples therapy (ABCT) who are experiencing a high degree of relationship distress benefit more from an extended treatment. For example, men with a lower level of relationship functioning had better drinking outcomes when receiving BCT followed by a relapse prevention intervention than BCT alone (McCrady et al., 2016b). Findings from a literature review conducted by McGovern et al. (2017) also suggest that for high-risk parents affected by substance misuse, more extended interventions are more effective (although the specific length is not specified).

4.7 Format of intervention

Findings from studies utilising a range of methods suggested that a group context for an intervention (i.e. including multiple families) can be effective for the children and families of those experiencing substance misuse. Group-based interventions could take a number of forms, including games, activities and informal opportunities for interaction with others experiencing similar challenges (Templeton, 2014; Lewis et al., 2014; Parliamentary Office of Science and Technology, 2018; Usher and McShane, 2015).

For the children of parents experiencing substance misuse, particularly, the experience of meeting and speaking to other children is something qualitative research has identified as important in facilitating the discussion of difficult experiences (Usher and McShane, 2015; Lewis et al., 2014; Templeton, 2014). One eight-week school-based programme focused on self-esteem and coping strategies within a psycho-educational approach for children of alcoholics, was found in a pre-post study to increase the children’s use of positive coping strategies and improved behaviour (Lewis et al., 2014). Where the whole family has been involved in group interventions, such as the M-PACT programme, the findings are also often positive. Adults in the family have also reported benefits from meeting and talking to others experiencing similar problems, as well as feeling less isolated (Templeton, 2014; Institute of public care, 2015, Syed et al., 2018).

While it is difficult to attribute positive outcomes experienced as a result of these programmes to its group format, as opposed to its content, in the case of M-PACT families clearly felt themselves to have benefitted from the group setting (Templeton, 2014). Further, rigorous evaluation is required before clear conclusions can be formed on exactly what form and content of group session is most effective for children and families. The impact of interventions in a group setting on the substance misuse of the affected parent was not discussed in the literature reviewed, however it appears plausible that group interventions could be an important source of support for those experiencing these issues as well.

There is also some evidence for the efficacy of interventions in a group setting on parental conflict and parenting practices (see Harold et al., 2016). In particular, interventions in a group format has been identified as a potential engagement strategy for couples experiencing high levels of conflict (Pote et al., 2019). Again, however, it is difficult to attribute the success of these programmes to their group format, but the findings are nevertheless promising.

As noted in section 3.3.2, interventions delivered to a couple can be more effective in tackling substance misuse than those delivered to the affected individual alone. There is strong evidence that the use of BCT results in greater reductions in substance misuse than the use of individual behavioural therapy alone (Schumm et al., 2014; Asmussen and Brims, 2018), although a blended approach appears to be even more effective (McCrady et al., 2016b). Moreover, the couples-based format of the intervention allows for the quality of the partner relationship to be improved at the same time (McCrady et al., 2016b; O’Farrell et al., 2017; Kelley et al., 2016; Easton, Crane and Mandel, 2017; Chanel and Wesley, 2015; Syed, Gilbert and Wolpert, 2018; Schumm et al., 2014).

There is also some evidence for the effectiveness of substance misuse interventions which include the family alongside the affected individual. Family format interventions have been shown in some cases to improve the motivation of the affected individual to change and thus reducing substance misuse, as well as improving communication in the family, family functioning and parenting practices (McCrady et al., 2016b; Daley et al., 2018; Parliamentary Office of Science and Technology, 2018; Syed, Gilbert and Wolpert, 2018; Templeton, 2014; Lewis et al., 2014; Usher and McShane, 2015). While the evidence for this approach is not totally conclusive, it does appear promising (Syed, Gilbert and Wolpert, 2018).

4.8 Technique or therapy deployed

As outlined in section 3.3, various techniques and therapies can be used successfully within substance misuse interventions. In particular, cognitive behavioural therapy (CBT) and behavioural couples therapy (BCT) are referenced frequently in the literature. CBT techniques are focused on the individual and can include functional analysis, self-management planning and skills training to manage the urge to use substances (Asmussen and Brims, 2018). BCT interventions employ these same techniques, as well as a number of others including a ‘sobriety contract’ in which the substance-using partner commits not to misuse substances and the non-using partner commits to support them, teaching the couple active listening skills, helping them to share in positive activities and developing a ‘continuing recovery plan’ to identify strategies for dealing with challenging situations to prevent relapse (Easton and Crane, 2016). There is evidence from a small number of studies to suggest that interventions are most successful when they combine CBT with BCT (McCrady et al., 2016b; O’Farrell et al., 2017). This may also be an effective way of overcoming the lack of preference of some women to BCT (McCrady et al., 2016b).

In addition, there is good evidence for the use of motivational interviewing (MI) as a tool to reduce substance misuse (Asmussen and Brims, 2018; Ward, Brown and Hyde-Dryden). MI seeks to engender behaviour change, through developing an individual’s motivation to change and mobilising their personal strengths and resources (McGovern et al., 2017). MI is not intended as a standalone treatment, but rather forms one part of, or acts as a precursor to, other treatments (Asmussen and Brims, 2018).

Ward, Brown and Hyde-Dryden (2014) report that MI has a slightly larger average effect size for illicit drug use than alcohol abuse. The authors also note, however, that effect sizes have been found to vary substantially across studies, even within the same problem areas. From this they infer that the way in which MI is delivered can have a big impact on its effectiveness. They also note that in a number of cases, the long-term impact of MI is uncertain, as while average effect size is relatively high in the first month after treatment, this quite quickly diminishes after three months to a year. Another study reported that there is no evidence of MI improving outcomes for the children of problematic alcohol users (Asmussen and Brims, 2018).

There is stronger evidence for the efficacy of MI in promoting engagement with interventions for substance misuse, as well as improving subsequent retention and adherence to attended programmes (Asmussen and Brims, 2018; Ward, Brown and Hyde-Dryden, 2014). Where MI was used in this way, effect sizes have been sustained or even increased over time (Ward, Brown and Hyde-Dryde, 2014). This might suggest that MI for the parent affected by substance misuse should be combined with other interventions such as BCT or CBT.

There is also some evidence to suggest that MI in combination with CBT can be used to target domestic abuse alongside substance misuse. Research has shown that treatment outcome is related to motivation to change for men in DA treatment, suggesting that the principles of MI might be particularly pertinent where a violence intervention is deemed necessary (Chermack et al., 2015). Chermack et al. (2015) conducted an RCT of an integrated violence prevention treatment combining MI and CBT, with the aim of minimising the patient’s resistance to the violence-specific element of the intervention. The first session heavily incorporated MI principles to build motivation to engage with the later sessions (which also contained some MI but were more skills focused and included CBT). The results showed a significant decline in alcohol use for the integrated treatment group, as well as in cocaine use and violence perpetration (although the latter two effects were also seen in the control condition). Cocaine use and drinking during the follow-up were found to predict post-treatment violence perpetration, suggesting that the integrated approach is promising in reducing the risk of this. The authors suggest, however, that continuing care approaches may be required after treatment completion in order to sustain any changes made.

4.9 Multi-agency working

A number of studies suggest that co-operation and co-ordination between multiple agencies is important in ensuring effective support for the full range of needs of the individual affected by substance misuse and their family.

The SKATE programme is one such example of an intervention in which family support services, child protection services and drug and alcohol services have worked together to provide support for families dealing with complex issues including substance misuse. A project worker was located at alcohol and drug services to help clinicians to identify individuals receiving treatment who were also experiencing wider issues in their family. This co-ordination aimed to ensure that where parents were brought to the attention of drug treatment services, the needs of their families and children were considered and the necessary processes put in place to protect and support them in the most appropriate setting (away from the drug treatment service) (Lewis et al., 2014).

Elsewhere, it has been suggested that in addressing the often-complex needs of an individual affected by substance misuse, it is better that this be done within one facility or agency. Easton and Crane (2016) suggest that if those requiring interventions for coexisting substance misuse and domestic abuse are required to go to different locations, then their motivation for engagement (often low already) will decrease. The authors also suggest, however, that a more significant problem with interventions happening separately is that agencies do not co-ordinate with each other, meaning that care is fragmented and inconsistent, and thereby less effective than if it was joined up. This suggests that the need for more co-ordination between different agencies is perhaps a more important point than the issue of an individual being required to go to two separate locations. The authors note that the large and complex case loads of such agencies make this a difficult problem to overcome.

4.10 Gaps in the evidence

This section presents a summary of the gaps in the evidence identified in sections 4.3 to 4.9.

• Intervention targeting: this review identified no evidence relating to interventions targeting non-dependent substance misuse.

• Engaging different sociodemographic groups: within the substance misuse literature, in particular, this review identified no evidence regarding the engagement of LGBTQ+ couples. The majority of studies focused on intact couples and did not consider divorced or separated couples. In addition, no studies examined the engagement or effectiveness of interventions for married couples compared to cohabiting couples.

In addition, the impact of socio-economic status on access, retention and outcomes for participants in substance misuse interventions was not directly addressed in the literature reviewed.

• Format of intervention: While there is some promising evidence to suggest that a group intervention is effective in helping the children and families of those who misuse substances, more research is required to ascertain what specific form and content of group session is most effective.

More generally, future research should attempt to isolate the particular element(s) of an intervention’s format or content which make it successful.

Appendix 1: Review protocol

This literature review deployed a rapid evidence assessment methodology. A review protocol consisting of two sets of predefined search terms, was agreed in partnership with DWP (see Figure 3 and Figure 4 for more detail of the search terms used). Two searches were then conducted using Google Scholar, from which the first 30 studies returned by each search term were used to develop a long-list bibliography, consisting of the full range of sources that might be relevant to the review. Alongside this, a targeted Google search was conducted to identify any relevant grey literature such as government policy papers not included in the academic databases.

The long-list bibliography was then distilled to a short-list bibliography, the contents of which was decided based on the following criteria.

• Study type: the inclusion criteria prioritised systematic reviews and literature reviews for research question one, as well as randomized control trials (RCTs) and quasi experimental studies of interventions for research question two. However, mixed-methods and qualitative studies, uncontrolled pre-post studies and grey literature documents were also included. All studies were scored in line with the Scientific Maryland Scale.

• Study origin: the inclusion criteria prioritised studies published in the UK or comparable countries, including the US and Australia.

• Publication date: only studies conducted since 2014 were included for review.

• Population: papers focused on parents and families were prioritised, and in particular those families experiencing both parental conflict and substance misuse. An overview of the data sources and study cohorts used by the UK studies included is outlined in Appendix 4.

• Intervention: for research question two, papers focused on interventions tackling both substance misuse and parental conflict were prioritised, as were papers focused on the impact of substance misuse interventions on parental conflict and children in the family.

While we prioritised studies meeting the above eligibility criteria, we did not always exclude studies targeting a non-parent population, or those which did not focus explicitly on the impact of interventions on both substance misuse and parental conflict, where it appeared likely that the study would contain content relevant to our research questions.

The short-list bibliography was sent to DWP for approval, and further grey literature was recommended for inclusion. At the end of this process a total of 66 studies were identified for inclusion in the review.

These sources were then used to generate evidence against each of the key questions put forward by DWP.

Appendix 2 contains a list of the documents reviewed. References given in this report refer to the sources listed here.

The impact on children

Primary search terms

Parental conflict

Family conflict

Family breakdown

Parental separation

Divorce

Domestic abuse

Domestic violence

Relationship breakdown

Secondary search terms

Substance misuse

Substance dependenc*

Alcohol

Drug*

Tertiary search terms for impact on outcomes

Child*

Impact

Outcome*

Adverse childhood experience*

Interventions and relative effectiveness

Primary search terms

Parental conflict

Family conflict

Family breakdown

Parental separation

Divorce

Domestic abuse

Domestic violence

Relationship breakdown

Secondary search terms

Substance misuse

Substance dependenc*

Alcohol

Drug*

Tertiary terms for interventions and effectiveness

Intervention*

Treatment

Programme*

Project*

Support*

Service*

Counsel*

Therap*

Evaluation

Efficacy

Appendix 2: Sources included for review

Acquah, D., Sellers, R., Stock, L and Harold, G. (2017) ‘Interparental conflict and outcomes for children in the contexts of poverty and economic pressure’, Early Intervention Foundation. Available: https://www.eif.org.uk/report/interparental-conflict-and-outcomes-for-children-in-the-contexts-of-poverty-and-economic-pressure/. Accessed: 01/08/2019.

Alonzo, D., Thompson, RG., Stohl, M., Hasin, D. (2014) ‘The influence of parental divorce and alcohol abuse on adult offspring risk of lifetime suicide attempt in the United States’, The American Journal of Orthopsychiatry, 84(3), pp:316-20.

Anderson, S. (2016) ‘Drinking Alone? The Effect of an Alcohol Treatment Program on Relationship Stability for Convicted Drunk Drivers in Denmark’, The ANNALS of the American Academy of Political and Social Science, 665(1).

Asmussen, K and Brims, L. (2018) ‘What works to enhance the effectiveness of the healthy child programme: an evidence update’, Early Intervention Foundation. Available: https://www.eif.org.uk/report/what-works-to-enhance-the-effectiveness-of-the-healthy-child-programme-an-evidence-update/. Accessed: 12/06/2019.

Barlow, J., Sembi, S., Parsons, H., Kim, S., Petrou, S., Harnett, P., Dawe, S. (2019) ‘A randomized controlled trial and economic evaluation of the Parents Under Pressure program for parents in substance abuse treatment’, Drug and Alcohol Dependence, 194, pp: 184-194.

Braitman, A and Kelley, M. (2016) ‘Initiation and Retention in Couples Outpatient Treatment for Parents with Drug and Alcohol Use Disorders’, Experimental and Clinical Psychopharmacology, 24(3), pp:174-184.

Brofenbrenner, U. (1994) ‘Ecological models of human development’ Readings on the development of children, 2(1), pp:37-43.

Callanan, M., Hudson, R., Husain, F., Roberts, E., Stock, L., & McBride, T. (2017). Exploring parental relationship support: a qualitative study, 1–82. Early Intervention Foundation. Available: https://www.eif.org.uk/report/exploring-parental-relationship-support-aqualitative-study. Accessed 12/06/2019.

Chanel, K and Wesley, C. (2015) ‘The use of behavioural couple therapy and couple-based interventions in the treatment of substance use disorders’, Addiction Research and Theory, 24(2), pp:89-92.

Charles, N., Ryan, S., Acheson, A., Mathias, C., Liang, Y and Dougherty, D. (2015) ‘Childhood stress exposure among preadolescents with and without family histories of substance use disorders’, Psychological Addictive Behaviour, 29(1), pp:192-200.

Chermack, S., Bonar, E and Ilgen, M. (2015) ‘Developing an Integrated Violence Prevention for Men and Women in Treatment for Substance Use Disorders’, Journal of Interpersonal Violence, 32(4), pp:581-603.

Children’s Commissioner’s Office (2019) ‘Childhood vulnerability in England in 2019’. Available: https://www.childrenscommissioner.gov.uk/publication/childhood-vulnerability-in-england-2019/. Accessed: 06/01/2020.

Daley, D., Smith, E., Balogh, D and Toscaloni, J. (2018) ‘Forgotten but Not Gone: The Impact of the Opioid Epidemic and Other Substance Use Disorders on Families and Children’, Commonwealth: A journal of Pennsylvania politics and policy, 20(2-3).

Department for Education (2018) ‘Statistics: children in need and child protection’. Available: https://www.gov.uk/government/collections/statistics-children-in-need. Accessed: 10/10/2019.

Department for Work and Pensions (2017a) ‘Improving Lives: Helping Workless Families’. Available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/621364/improving-lives-helping-workless-families-web-version.pdf. Accessed: 01/08/2019.

Department for Work and Pensions (2017b) ‘Improving Lives: Helping Workless Families indicators 2017 and evidence base’. Available: https://www.gov.uk/government/publications/improving-lives-helping-workless-families-evidence-base

Department for Work and Pensions (2018) ‘Parental conflict indicator 2011/12 to 2015/16’. Available: https://www.gov.uk/government/statistics/parental-conflict-indicator-201112-to-201516. Accessed: 08/10/2019.

Department for Work and Pensions (2019) ‘Information about the Reducing Parental Conflict Programme’. Available: https://www.gov.uk/government/publications/reducing-parental-conflict-programme-information-for-stakeholders/information-about-the-reducing-parental-conflict-programme. Accessed: 01/08/2019.

Easton, E and Crane, C. (2016) ‘Interventions to reduce intimate partner violence perpetration among people with substance use disorders’, International Review of Psychiatry, 28(5), pp:533-543.

Easton, E., Crane, C and Mandel, D. (2017) ‘A Randomized Controlled Trial Assessing the Efficacy of Cognitive Behavioral Therapy for Substance‐Dependent Domestic Violence Offenders: An Integrated Substance Abuse‐Domestic Violence Treatment Approach (SADV)’, Journal of Martial and Family Therapy, 44(3), pp:483-498.

Fergusson, D., McLeod, G., Horwood, L.J. (2014) ‘Parental separation/divorce in childhood and partnership outcomes at age 30’, The Journal of Child Psychology and Psychiatry, 55(4), pp:352-360.

Finan, L., Schulz, J., Gordon, M., McCauley Ohannessian., C.M (2015) ‘Parental problem drinking and adolescent externalizing behaviors: The mediating role of family functioning’, Journal of Adolescence, 43, pp:100-110.

Ford, K., Butler, N., Hughes, K., Quigg, Z and Bellis, M. (2016) ‘Adverse Childhood Experiences (ACEs) in Hertfordshire, Luton and Northamptonshire’, Centre for Public Health, Liverpool John Moores University. Available: https://www.researchgate.net/publication/302589403_Adverse_Childhood_Experiences_ACEs_in_Hertfordshire_Luton_and_Northamptonshire/link/5731c77a08ae08415e6b8efd/download. Accessed: 12/06/2019.

Gilchrist, G., Radcliffe, P., Regina Noto, A., Flavia Pires Lucas d’Oliveira, Ana. (2019) ‘The prevalence and factors associated with ever perpetrating intimate partner violence by men receiving substance use treatment in Brazil and England: A cross-cultural comparison’, Drug and Alcohol Review, 36(1), pp:34-51.

Harold, G., Acquah, D., Sellers, R and Chowdry, H. (2016) ‘What works to enhance interparental relationships and improve outcomes for children?’, Early Intervention Foundation. Available: https://www.eif.org.uk/report/what-works-to-enhance-interparental-relationships-and-improve-outcomes-for-children/. Accessed: 12/06/2019.

Horigian, V., Feaster, D., Brincks, A., Robbins, M., Alejandra Perez, M and Szapocznik, J. (2015) ‘The effects of Brief Strategic Family Therapy (BSFT) on parent substance use and the association between parent and adolescent substance use’, Addictive Behaviors, 42, pp:44-50.

Hughes, K., Lower, H., Quigg Z and Bellis, M. (2016) ‘Relationships between adverse childhood experiences and adult mental well-being: results from an English national household survey’, BMC Public Health, 16(222).

Hutchinson, D., Mattick, R., Braunstein, D., Maloney, E., Wilson, J. (2014) ‘The Impact of Alcohol Use Disorders on Family Life: A Review of the Empirical Literature’, National Drug and Alcohol Research Centre, University of New South Wales. Available: https://www.researchgate.net/publication/274634313_The_impact_of_alcohol_use_disorders_on_family_life_A_review_of_the_empirical_literature/link/5523e52c0cf24f160943b2d4/download. Accessed: 12/06/2019

Institute of Public Care. (2015) ‘Hampshire County Council: Working with Families where there is Domestic Violence, Parent Substance Misuse and/or Parent Mental Health Problems’. Available: https://ipc.brookes.ac.uk/files/publications/Rapid_Research_Review_relating_to_Toxic_Trio_Families_December_2015.pdf Accessed: 12/06/2019.

Jennison, K. (2014) ‘The impact of parental alcohol misuse and family environment on young people’s alcohol use and behavioral problems in secondary schools’, Journal of Substance Use, 19 (1-2), pp:2016-2012.

Keeley, H., Mongwa, T and Corcoran, P. (2015) ‘The association between parental and adolescent substance misuse: findings from the Irish CASE study’ Irish Journal of Psychological Medicine, 32 (1), pp:107-116.

Kelley, M., Bravo, A., and Braitman, A. (2017) ‘Behavioral Couples Treatment for Substance Use Disorder: Secondary Effects on the Reduction of Youth Internalizing Symptoms’, Journal of Abnormal Child Psychology, 45(4), pp:731-741.

Kelley, M., Bravo, A., Braitman, A., Lawless, A., Lawrence, M. (2016) ‘Behavioral Couples Treatment for Substance Use Disorder: Secondary Effects on the Reduction of Risk for Child Abuse’, Journal of Substance Abuse Treatment, 62, pp:10-19.

Ladd, B and McCrady, B. (2015) ‘Typology of Couples Entering Alcohol Behavioral Couple Therapy: An Empirical Approach and Test of Predictive Validity on Treatment Response’, Journal of Marital and Family Therapy, 42(1), pp:62-75.

Laslett, A, Mugavin, J, Jiang, H, Manton, E, Callinan, S, Maclean, S and Room, R. (2015) ‘The hidden harm: alcohol’s impact on children and families. Canberra: Foundation for Alcohol Research and Education’, Foundation for Alcohol Research and Education, pp:128.

Leung, J., Britton, A and Bell, S. (2016) ‘Adverse Childhood Experiences and Alcohol Consumption in Midlife and Early Old-Age’, Alcohol and Alcoholism, 51(3), pp:331-338.

Lewis, A., Holmes, N, Watkins, B and Mathers, D. (2014) ‘Children Impacted by Parental Substance Abuse: An Evaluation of the Supporting Kids and Their Environment Program’, Journal of Child and Family Studies, 24(8), pp:2398-2406.

McCrady, B., Epstein, E., Hallgren, K., Crook, S and Jensen, N. (2016a) ‘Women with alcohol dependence: A randomized trial of couple versus individual plus couple therapy’, Journal of the Society of Psychologists in Addictive Behaviors, 30(3), pp:287-299.

McCrady, B., Wilson, A, Munoz, R., Fink, B., Fokas, K and Borders, A. (2016b) ‘Alcohol‐Focused Behavioral Couple Therapy’, Family Process, 55(3), pp:443-459.

McGovern, R., Gilvarry, E., Addison, M., Alderson, H., Carr, L., Geijer-Simpson, E., Hrisos, N., Lingam, R., Minos, D., Smart, D and Kaner, E. (2018) ‘Addressing the impact of nondependent parental substance misuse upon children’, Public Health England. Available: http://www.fuse.ac.uk/research/earlylifeandadolescence/outputsfromprogramme/McGovern_Addressing%20the%20impact%20of%20parental%20non-dependent%20substance%20misuse%20upon%20the%20child_PS_FINAL%20DRAFT.pdf. Accessed: 12/06/2019.

McLaughlin, A., O’Neill, T., McCartan, C., Percy, A., McCann, M., Perra, O and Higgins, K. (2015) ‘Parental Alcohol Use and Resilience in Young People in Northern Ireland: A study of family, peer and school processes’, Institute of Child Care Research. Available: https://research.hscni.net/sites/default/files/Final%20Report_1.pdf. Accessed: 12/06/2019.

Ministry of Housing, Communities and Local Government. (2019) ‘National Evaluation of the Troubled Families Programme 2015-2020: Findings.’ Available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/786889/National_evaluation_of_the_Troubled_Families_Programme_2015_to_2020_evaluation_overview_policy_report.pdf. Accessed: 12/06/2019.

Neger, E and Prinz, R. (2015) ‘Interventions to address parenting and parental substance abuse: Conceptual and methodological considerations’, Clinical Psychology Review, pp:71-82.

NSPCC. (2018) ‘Children living in families facing adversity’. Available - https://learning.nspcc.org.uk/media/1432/nspcc-families-facing-adversity-helplines-report.pdf Accessed: 12/06/2019.

O’Farrell, T., Schumm, J., Murphy, M and Muchowski, P. (2017) ‘A randomized clinical trial of behavioral couples therapy versus individually-based treatment for drug-abusing women’, Journal of Consulting and Clinical Psychology, 85(4), pp:309-322.

Park, S and Schepp, K. (2015) ‘A Systematic Review of Research on Children of Alcoholics: Their Inherent Resilience and Vulnerability’, 24(5), pp:1222-1231.

Parliamentary Office of Science and Technology (2018) ‘Parental Alcohol Misuse and Children’ Available: https://researchbriefings.files.parliament.uk/documents/POST-PN-0570/POST-PN-0570.pdf. Accessed: 12/06/2019.

Poute, I., Doubell, L., Brims, L., Larbie, J., Stock, L. and Lewing, B. (2019) ‘Engaging disadvantaged and vulnerable parents: An evidence review’ Available: https://www.eif.org.uk/report/engaging-disadvantaged-and-vulnerable-parents-an-evidence-review. Accessed: 08/10/2019.

Pryce, R., Buykx, P., Gray, L., Stone, T., Drummond, C., and Brennan, A. (2017) ‘Estimates of alcohol dependence in England based on APMS 2014, including estimates of children living in a household with an adult with alcohol dependence’, University of Sheffield, King’s College, London. Available: https://www.sheffield.ac.uk/polopoly_fs/1.693546!/file/Estimates_of_Alcohol_Dependence_in_England_based_on_APMS_2014.pdf Accessed: 08/10/2019.

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Rounsaville, D., O’Farrel, T., Burdzovic Andreas, J., Murphy, C and Murphy, M. (2014) ‘Children’s exposure to parental conflict after father’s treatment for alcoholism’, Addictive Behaviors, 39(7), pp:1168-1171.

Sabates and Dex. (2015) ‘The impact of multiple risk factors on young children’s cognitive and behavioural development’, Children and Society, 29(2), pp: 95-108.

Schumm, J., O’Farrell, T., Kahler, C., Murphy, M and Muchowski, P. (2014) ‘A randomized clinical trial of behavioral couples therapy versus individually based treatment for women with alcohol dependence’, Journal of Consulting and Clinical Psychology, 82(6), pp:993-1004.

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Siegel, J. (2014) ‘Emotional Regulation in Adolescent Substance Use Disorders: Rethinking Risk’, Journal of Child and Adolescent Substance Abuse, 24(2), pp:67-79.

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Syed, S., Gilbert, R and Wolpert, M. (2018) ‘Parental Alcohol Misuse and the Impact on Children: A Rapid Evidence Review of Service Presentations and Interventions’, Children’s Policy Research Unit. Available: https://www.ucl.ac.uk/children-policy-research/sites/children-policy-research/files/parental-alcohol-misuse-and-impact-on-children.pdf. Accessed: 12/06/2019.

Templeton, L. (2014) ‘Supporting families living with parental substance misuse: the M‐PACT (Moving Parents and Children Together) programme’, Child and Family Social Work, 19(1), pp:76-88.

Usher, A and McShane, K. (2016) ‘Supporting Children of Substance Abusing Families: Preliminary Outcomes of the Renascent Children’s Program’, Journal of Groups in Addiction and Recovery, 11(4), pp:282-295.

Velleman, R and Templeton, L. (2016) ‘Impact of parents’ substance misuse on children: an update’, BJPsych Advances, 22(2), pp:108-117.

Victor, B., Grogan-Kaylor, A., Ryan, J., Perron, B and Gilbert, T. (2018) ‘Domestic violence, parental substance misuse and the decision to substantiate child maltreatment’, Child Abuse and Neglect, 79, pp:31-41.

Wade, R., Cronholm, P., Fein, J., Forke, C., Davis, M., Harkins-Schwarz, M., Pachter, L and Bair-Merritt, M. (2016) ‘Household and community-level Adverse Childhood Experiences and adult health outcomes in a diverse urban population’ Child Abuse and Neglect, 52, pp:135-145.

Waldron, M., Watkins, N., Bucholz, K., Madden, P and Heath, A. (2018) ‘Interactive Effects of Maternal Alcohol Problems and Parental Separation on Timing of Daughter’s First Drink’, Alcoholism: Clinical and Experimental Research, 42(1), pp:120-127.

Ward, H., Brown, R and Hyde-Dryden, G. (2014) ‘Assessing Parental Capacity to Change when Children are on the Edge of Care: an overview of current research evidence’ Centre for Child and Family Research, Loughborough University, and Department for Education. Available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/330332/RR369_Assessing_parental_capacity_to_change_Final.pdf. Accessed: 12/06/2019.

Wilson, I., Graham, I and Taft, A. (2014) ‘Alcohol interventions, alcohol policy and intimate partner violence: a systematic review’, BMC Public Health, 14.

Windle, M and Windle, R. (2018) ‘Parental Divorce and Family History of Alcohol Disorder: Associations with Young Adults’ Alcohol Problems, Marijuana Use, and Interpersonal Relations’, Alcoholism: Clinical and Experimental Research, 42(6), pp:1084-1095.

Appendix 3: Separation and Divorce

Parental separation or divorce are associated with a broad range of family problems, including increased exposure of children to interparental conflict (Fergusson et al., 2014). This association means that the impact of coexisting parental separation/divorce and substance misuse on outcomes for children may help to explain the role of conflict. Separation/divorce is also easier to measure than parental conflict, which often relies on various subjective measures which vary significantly across studies. The relationship between substance misuse and separation/divorce appears to be similar to that shown to exist between substance misuse and parental conflict. Alcohol misuse by at least one partner has been shown to be predictive of separation and divorce (McLaughlin et al., 2015; Hutchinson et al., 2014; Waldron et al., 2017).

With regards to the impact on children, while there is well-established evidence for divorce increasing the risk of negative developmental outcomes, less is known about the risks faced by children experiencing both parental separation/divorce and substance misuse. For some time, there has been an established body of evidence to suggest that parental alcohol problems experienced in combination with parental separation/divorce predicts an increased risk of negative outcomes in the children and family (reported in Alonzo et al., 2014; Waldron et al., 2017; Windle and Windle., 2017). A longitudinal study of a New Zealand birth cohort found that the association between experiencing parental separation/divorce as a child and having negative partner relations in adulthood was explained by a series of covariate factors including parental history of illicit drug use and interparental conflict (as well as others including family socioeconomic status at time of the child’s birth). The authors suggest that these factors could have acted as confounders, influencing both the likelihood of separation or divorce occurring and the risk of negative outcomes for the child. Alternatively, they suggest that they could have acted as intervening variables which reflect the consequences of separation on childhood circumstances (Fergusson et al., 2014).

The evidence regarding this interaction is inconclusive, however, as illustrated in a study conducted by Alonzo et al. (2014) in the US. The study used data from a national epidemiological survey on alcohol and related conditions, and found evidence to suggest that both divorce and parental alcohol abuse, independently of one another, are associated with an increased risk of lifetime suicide attempt in the children of the family. The study found, however, that the variables did not interact to differentially increase the risk of suicide attempt in the adult children studied. Separately, a large twin cohort study conducted in the US found that while both parental separation and parental alcohol problems are associated with early-onset drinking by offspring, separation actually acted to moderate the risk of early-onset drinking associated with mother-only alcohol problems, although not with paternal alcohol problems (Waldron et al., 2017). A developmental study of US teenagers, examining the joint contribution of parental divorce and FH+ on young adult development measures, found that contrary to the authors’ hypothesis there was no interaction between the variables in leading to worse outcomes for children. The only exception to this was combined maternal alcoholism and divorce predicting higher marijuana use among offspring (Windle and Windle, 2018). The results of these studies go against previous findings which have suggested that children of separated parents with a history of alcohol abuse are at greater risk of negative outcomes than those dealing with either experience independently.

While one explanation of these findings is that separation/divorce removes a child from the alcohol abusing parent, follow-up analyses conducted with those in the twin cohort, which focused on maternal alcoholism, found that nearly all children continued to reside with the affected mother (Waldron et al., 2017). Alonzo et al. (2014) suggest that the reason for this finding could be that parents who abuse substances are also likely to experience high levels of parental conflict and poor parent-child interaction. It could be, therefore, that separation/divorce can serve to limit this conflict by separating the parents, removing an additional risk factor for children that may encourage suicidal behaviour. Rather than acting as a proxy for conflict, therefore, divorce could be used as a proxy for its cessation. Other explanations were also suggested, such as the idea that separation might be more expected, and so produce les confusion and resentment. These mechanisms require more thorough exploration and testing in future, but it appears to be the case that separation or divorce can sometimes be a positive event for children in families experiencing substance misuse.

Appendix 4: Data sources used by the studies reviewed

In this section we outline the data sources used for the UK studies reviewed, with a view to identifying potentially useful sources of information for the design of future interventions and policy. In the main, the UK studies reviewed either made use of data from existing large national cohort studies, or conducted their own surveys focused on a particular cohort.

The national cohort studies used include the following:

• Belfast Youth Development Study, a prospective study of 1,000 families conducted over ten years and focused specifically on substance misuse of children and parents (McLaughlin et al., 2015).

• Millennium Cohort Study, a study of 19,000 children born across the UK between 2000-01 (Sabates and Dex, 2015)

• Health Survey for England and the General Household Survey, both UK government sponsored (McLaughlin et al., 2015)

• Children in need census, data collected by the UK government on all children referred to local authority care services due to their health or development being put at risk (Department for Education, 2018).

Whitehall II study, a cohort of over 10,000 participants working in the British Civil Service in 1985, from whom data regarding psychosocial factors and health conditions is collected every two to five years (Leung, Britton and Bell, 2015).

Cohort studies conducted specifically for the studies reviewed include:

• a nationally representative household survey of 3,884 English adults focused on measuring mental wellbeing and retrospective exposure to ACEs (Hughes et al., 2016)

• a cross-sectional survey of 5,454 adults living in Hertfordshire, Luton and Northamptonshire to determine retrospective exposure to ACEs as well as health-harming behaviours and mental wellbeing (Ford et al., 2016).

Appendix 5: Overview of interventions

The below table presents an overview of the interventions outlined in section 3.3, including the evidence reviewed for each, the population the intervention relates to and its effect. Also included are which of the five subsets of outcome measures outlined in section 3.5 the intervention relates to: substance use outcomes; relationship outcomes; parenting outcomes; domestic abuse outcomes and; children’s outcomes.

Overview of interventions included for review

Substance misuse interventions delivered to the individual parent

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
4 programmes including inpatient/residential treatment, intensive day treatment and outpatient counselling.	1 quasi-experimental	Fathers in treatment for alcohol dependence and their female partners	Substance misuse Relationship Children	Significant effects	Rounsaville et al. (2014)
Psychological interventions – e.g. brief motivational interviewing (MI), cognitive behavioural therapy (CBT) and community reinforcement (CR)	1 systematic review	Parents in substance misuse treatment (drug and alcohol)	Substance misuse Relationship Children	Mixed results	McGovern et al. (2018)
Intensive case management intervention	1 systematic review	Parents who misuse substances	Substance misuse	Significant effects	McGovern et al. (2018)

Substance misuse interventions delivered to the couple

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
Behavioural couples therapy (BCT)	1 systematic review 2 RCTs	Intact couples in which one or both partners has a substance use disorder	Substance misuse Relationship	Significant effects	Asmussen and Brims (2018) Schumm et al. (2014)
BCT	1 literature review 2 uncontrolled pre-post studies	Intact parenting couples in which one or both partners has a substance use disorder	Substance misuse Relationship Children	Significant effects on substance misuse and parental conflict. Mixed results for child outcomes.	Kelley et al. (2016), Kelley, Bravo and Braitman (2017), Syed, Gilbert and Wolpert (2018)
Alcohol behavioural couples therapy (ABCT)	1 literature review	Intact couples in which one or both partner has an alcohol use disorder	Substance misuse Relationship Domestic abuse	Significant effects	McCrady et al (2016b)
Blended-ABCT (alcohol behavioural couple therapy + individual CBT)	1 RCT	Women with alcohol use disorder (AUD) and their male partners.	Substance misuse Relationship	Non-significant effects compared to ABCT alone	McCrady et al (2016a)
BCT + individual behavioural therapy	1 RCT	Women with AUD and their male partners	Substance misuse Relationship Domestic abuse	Significant effects	Schumm et al (2014)

Substance misuse interventions delivered to the family

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
Moving Parents and Children Together (M-PACT) programme	1 qualitative 1 literature review.	Children and families affected by parental substance misuse	Relationship Children Parenting	Positive findings, but only qualitative.	Templeton (2014), Parliamentary Office of Science and Technology (2018).
Strengthening Families Programme (SFP)	1 literature review	Parents and children affected by parental substance misuse	Children Parenting	Significant effects (but limited to QED studies, qualitative and uncontrolled pre-post studies)	Syed, Gilbert and Wolpert (2018)
Family therapy e.g. multi-systemic family therapy	1 literature review	Parents and children affected by parental substance misuse	Substance misuse	Moderate effects	Syed, Gilbert and Wolpert (2018)
Brief Strategic Family Therapy (BSFT)	1 RCT	Families in which both parent and adolescent use substances	Substance misuse Relationship Children	Significant effects	Horigian et al. (2015)
Supporting Kids and Their Environment (SKATE)	1 uncontrolled pre-post study	Parents and children affected by parental substance misuse	Children Parenting	Significant effects	Lewis et al. (2014)
The Children’s Program	1 uncontrolled pre-post study	Parents and children affected by parental substance misuse	Children Parenting	Significant effects	Usher and McShane (2016)
Intensive case management - e.g. Intensive family preservation service (IFPS)	1 systematic review, 1 review	Parents and children affected by parental substance misuse	Substance misuse ChildrenParenting	Moderate effects on improved family functioning (no effects in preventing out-of-home child placement)	Syed, Gilbert and Wolpert (2018), McGovern et al (2018)

Parenting programmes for parents affected by substance misuse

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
Home-visiting programmes - e.g. parents under pressure	1 literature review 1 uncontrolled pre-post study 2 RCTs	Parents affected by substance misuse and their children	Substance misuse Children Parenting	Significant effects on child maltreatment risk. No effect on substance misuse above treatment as usual.	Institute of public care (2015) Peisch et al (2018) Lewis et al (2014)
Parenting interventions combined with substance misuse treatment	1 systematic review	Parents affected by substance misuse	Substance misuse Parenting	Significant effects on parenting, no effect on substance misuse above treatment as usual.	Neger and Prinz (2015)
Brief parenting skills intervention (delivered in primary care)	1 literature review	Parents affected by substance misuse	Substance misuse	Moderate effects in improving parents’ treatment engagement	Syed, Gilbert and Wolpert (2018)
BCT combined with parenting intervention	1 systematic review	Parents affected by substance misuse	Substance misuse Children	Significant effects	Asmussen and Brims

Domestic abuse and substance misuse interventions

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
Integrated treatment options – e.g. CBT to tackle both substance misuse and DA	1 literature review 1 RCT	Men with substance abuse disorder and a history of perpetrating DA	Substance misuse Domestic abuse	Significant effects	Easton and Crane (2016), Easton, Crane and Mandel (2018)
BCT combined for couples affected by DA	2 literature reviews	Couples choosing to remain together after DA	Substance misuse Domestic abuse	Mixed results. Some studies showing significant effects on DA and SM	Wilson, Graham and Taft (2014), McCrady et al. (2016b)
Multi-couple group therapy	1 systematic review	Couples choosing to remain together after DA	Substance misuse Domestic abuse	Significant effects	Easton, Crane and Mandel (2017)

Criminal justice system

Intervention	Evidence reviewed	Study cohort	Outcomes impacted	Effect	References
Family drug and alcohol court (FDAC) trials	1 systematic review 2 literature reviews	Parent affected by substance misuse (when child taken into care)	Substance misuse Children	Significant effects in increasing abstinence and improving reunification rates. Long-term outcomes for children unclear.	McGovern et al (2018), Asmussen and Brims (2018) Ward, Brown and Hyde-Dryden (2014)

1. For a definition of domestic abuse, see https://www.cps.gov.uk/domestic-abuse. ↩

2. Only a brief overview of headline findings is provided here. We recommend referring to original resources for more in-depth information. ↩

3. Siegel (2014) argues that both externalising and internalising behaviours are associated with an increased risk of substance misuse in children, but via different mechanisms. A lack of self-control reportedly increases the risk of substance misuse in children experiencing externalising behaviour, whereas in those children experiencing internalising problems it is their negative emotionality which increases risk. ↩

4. There is no one definition of ACEs, but experiences included are typically those related to a child’s household and family environment, as well as experience of maltreatment. Definitions of ACEs always contain reference to parental substance misuse. Parental conflict is less frequently included, although parental divorce and domestic abuse usually are. A typical list includes the following (taken from Bellis et al., 2016):
   
   (a) Verbal, physical and/or sexual abuse;
   (b) Parental divorce/separation;
   (c) Household mental illness;
   (d) Household domestic abuse;
   (e) Household alcohol and/or drug abuse; and
   (f) Incarceration of a household member.
   
   It is relatively common for a child in the UK to experience one or more ACE. A cross-sectional study of adults in Wales conducted by Bellis et al. (2016) found that 47% of respondents experienced at least one ACE, and 14% experienced four or more. This is supported by the findings of a study by Ford et al. (2016) of ACEs in Hertfordshire, Luton and Northamptonshire, in which one in 10 respondents had experienced four or more ACEs. ↩

5. The 10 risk factors are: parental depression; parental physical disability; parental substance misuse; parental alcoholism; parental domestic violence; financial stress; parental worklessness; parental teenage parenthood; basic skills (lack of); overcrowding. ↩

6. “Four-risk combinations” refer to instances in which children present with four out of the ten risk factors measured by the study. ↩

7. Substance misuse interventions delivered to the couple include some delivered to couples who are not necessarily parents. ↩

8. Although the specific duration required is not defined. ↩

9. Some of the studies included in this section also assessed the impact of BCT on domestic abuse. These findings are discussed in section 3.3.5. Also included in section 3.3.5 are studies where BCT interventions have been specifically targeted at a cohort of perpetrators of domestic abuse. ↩

10. Emotional regulation was measured via engagement in ‘goal-directed behaviours’, impulse control and emotional awareness (Barlow et al., 2019) ↩

11. The interventions detailed in sections 3.3.1 to 3.3.4 may also impact on DA, but this is not an explicit aim of the programme or a focus of the studies included. ↩

12. For a list of outcome measures used by services delivering relationship crisis support (without a focus on substance misuse), please see Callanan et al., 2017. ↩