Research and analysis

An assessment of the evidence on conversion therapy for sexual orientation and gender identity

Published 29 October 2021

1. Executive summary

This report summarises the international evidence on the nature, quality and quantity of evidence on conversion therapy to change sexual orientation, and to change gender identity. This is to help inform the development of options for ending conversion therapy.

This assessment supplements the rapid evidence review and research on conversion therapy carried out by Coventry University.

1.1 About the evidence

The evidence base for conversion therapy to change sexual orientation has been growing for over 20 years. The evidence base for gender identity is much newer, with the earliest study done in 2018. As a result, the literature is dominated by evidence on conversion therapy for sexual orientation.

The main topics of the studies into conversion therapy for sexual orientation were:

• participants’ experiences of conversion therapy
• the outcomes of conversion therapy

For conversion therapy for gender identity, the main topics covered were:

• the scale of conversion therapy among transgender people
• participants’ experiences of conversion therapy
• the outcomes of conversion therapy

Articles were reviewed using a standardised assessment approach, with each study scored on a spectrum from ‘high’ to ‘average’ to ‘low’, including points in between. Most of the studies were assessed as being of around average quality.

However, the quality of the overall evidence base is lowered by the lack of robust sampling and design in the quantitative studies. This is because a sample frame of people who have undergone conversion therapy does not exist.

There were a small number of studies for conversion therapy for gender identity and these were assessed as being stronger in design than those for sexual orientation. This was due to the fact that 2 of the studies were based on large-scale national surveys, which helps to reduce some sample limitations.

1.2 Main findings

The main findings from the studies were that:

• there is no robust evidence that conversion therapy can achieve its stated therapeutic aim of changing sexual orientation or gender identity
• the types of practices tend to be similar for conversion therapy for sexual orientation and for gender identity – for example, talking therapies delivered by faith groups or mental health professionals
• conversion therapies were associated with self-reported harms among research participants who had experienced conversion therapy for sexual orientation and for gender identity – for example, negative mental health effects like depression and feeling suicidal
• there is indicative evidence from surveys that transgender respondents were as likely or more likely to be offered and receive conversion therapy than non-transgender lesbian, gay or bisexual (LGB) respondents

1.3 Issues for consideration

Based on the reported aims of studies, it was possible to categorise them by their focus on conversion therapy for sexual orientation or for gender identity.

However, some of the studies targeted at changing sexual orientation also included changing people’s social identities, which could affect their gender identity. As a result, a number of studies have suggested that practitioners of conversion therapy can conflate sexual orientation and gender identity in practice.

This assessment also found this area of research faces some inherent methodological challenges which are highlighted throughout. This limits the ability to say definitively what the impact of conversion therapy is.

However, this report has noted that the quality of evidence reviewed is likely to be the highest possible given inherent constraints. More methodologically-robust research designs, such as randomised control trials, are not possible.

While the evidence is based on self-reporting, consistent patterns were found which enable conclusions to be drawn. These are that there is no robust evidence that conversion therapy can change sexual orientation or gender identity, and that conversion therapy is frequently associated with harm.

2. Introduction

The National LGBT Survey 2017 had a self-selecting sample of around 108,000 lesbian, gay, bisexual, and transgender (LGBT) respondents in the UK. The survey found that:

• 5% of respondents said they had been offered conversion or reparative therapy in an attempt to cure them of being LGBT
• a further 2% said they had undergone the therapy

These figures were higher for transgender respondents, with 13% saying they had undergone or been offered conversion therapy, compared with 7% of non-transgender UK respondents. In 2018, the government said it would explore options for ending conversion therapy in the UK.

The Government Equalities Office (GEO) commissioned a further study, comprising a rapid evidence assessment and qualitative research, to improve understanding of the practice, experience and effect of conversion therapies.

This was undertaken by researchers at Coventry University and aimed to answer questions such as:

• what forms does conversion therapy take?
• who experiences conversion therapy and why?
• what are the outcomes of conversion therapy?
• what measures have been taken to end conversion therapy around the world?

GEO’s assessment aims to distinguish between evidence on conversion therapy for sexual orientation and for gender identity. This analysis builds on the evidence review and findings generated by Coventry University. It does not replace it, but considers a further question:

• to what extent does the evidence vary for conversion therapy to change sexual orientation and gender identity, specifically in relation to its nature, quality, quantity and the findings?

This report summarises the findings from this analysis.

3. Approach

3.1 Search strategy

The research team at Coventry University found 46 articles in their rapid evidence assessment on conversion therapy. These articles are listed in Appendix 1.

These 46 studies were used as a starting point for the evidence search for this assessment. We used an academic database to look for any other relevant studies, using the terms:

• ‘conversion therapy’ or ‘reparative therapy’
• ‘sexual orientation’ or ‘gender identity’

We also did research to identify any further grey literature relating to this issue, but did not find any more studies.

3.2 Assessment

Full text articles were read and reviewed and their methodology assessed using the Mixed Methods Appraisal Tool (MMAT) (Pluye and others, 2009), which we felt gave a consistent set of questions across a broad range of methods. For example, compared with other tools, the MMAT specifically includes criteria for appraising mixed methods studies.

The MMAT can be used to appraise the quality of 5 categories of study:

• qualitative research
• randomised controlled trials
• non-randomised studies
• quantitative descriptive studies
• mixed methods studies

Systematic reviews cannot be assessed using the MMAT. Instead the methods and search strategies of the 3 systematic reviews found were reviewed for robustness independently.

The MMAT uses up to 5 different questions for each type of study. For example, for quantitative studies reviewers are asked to assess whether the statistical analysis used is appropriate. For qualitative studies, they are asked whether the conclusions taken from the data presented are rational. Each question is answered with a ‘yes’ or ‘no’, and an overall score is given. Reviewers also make notes about the studies’ strengths and limitations. All of this contributes to an overall assessment of quality. This approach was in line with that taken in the Coventry University review.

For this exercise each study was scored in this way. Its quality was then labelled as one of the following:

• high
• above average
• average
• below average
• low

All full text articles were reviewed by one analyst using the relevant MMAT section. This gave an indication of the quality of each study. A random sample of 10% of the studies were also reviewed by a second analyst and these scores were compared for consistency and reliability.

A matrix was developed to catalogue the studies. Information was captured from each study under the following headings:

• coverage – for example, sexual orientation, gender identity or both
• geography – for example, country in which the study was carried out
• methodology – for example, comparison group, pre-post survey, qualitative
• overall assessment of quality – for example, how robust the study was
• topic or focus of the study – for example, experience or impact of conversion therapy
• main findings

We identified patterns from this exercise, such as the similarities and differences between the studies looking at conversion therapy for sexual orientation and gender identity. Main findings on the patterns in the evidence between conversion therapy for sexual orientation and gender identity are shown in the next 4 sections. A high-level summary using the matrix headings is shown in Appendix 2. The full assessment is available as a separate annex.

4. Overview of the evidence

46 studies were found relating to conversion therapy, including 26 from the USA and only 2 from the UK. This makes evaluating the evidence within a UK context challenging.

The evidence base for conversion therapy to change sexual orientation has been growing for over 20 years. The evidence base for gender identity is much newer, with the earliest study done in 2018. Given this, most studies in this assessment focus exclusively on conversion therapy for sexual orientation (41 out of 46).

4 studies looked exclusively at conversion therapy for gender identity, and one further study looked at experiences of conversion therapy on the basis of respondents’ sexual orientation or gender identity.

Based on the reported aims of the studies, it is possible to categorise them by their focus on conversion therapy for sexual orientation or for gender identity. However, some of the studies targeted at changing sexual orientation also extended to changing people’s social identities, which could affect their gender identity. This suggests in the evidence that practitioners of conversion therapy can mix sexual orientation and gender identity in practice.

The main topics of the studies reviewed were:

• the scale of conversion therapy and people’s experiences of it (including their experiences within organisations promoting it)
• an assessment of how effective conversion therapy was at achieving its stated therapeutic aims (including any associated outcomes)

Using the MMAT approach the largest proportion of studies were assessed as being of around average quality (either average, or slightly above or below). Overall the quality assessment is lowered by the lack of robust sampling and design in the quantitative studies, 2 of the factors used in the MMAT scoring.

Studies on conversion therapy for gender identity were assessed as being stronger in design than those for sexual orientation, despite being fewer in number. This is felt to be due to their larger sample sizes, drawing on data from large-scale national surveys and appropriate or standardised measures, which can help to reduce sampling limitations.

The evidence base on conversion therapy as a whole is limited by clear methodological challenges – but more methodologically robust research designs such as randomised control trials are not possible. This is inherent with research in this topic area – more robust research designs would mean allocating some participants to a group who then went on to undergo conversion therapy, and comparing them to a group who did not. This would be practically and ethically impossible.

It is therefore important to note that the quality of evidence identified in this assessment will be the highest that is achievable, drawing on data from interviews and surveys in which participants reflect on their experiences and the impact conversion therapy has had on them.

5. Conversion therapy for sexual orientation and gender identity

Although the evidence base on conversion therapy is relatively limited, the findings from studies are generally consistent for both sexual orientation and gender identity.

Studies on conversion therapy for both sexual orientation and gender identity show that:

• there is no robust evidence that conversion therapy can change sexual orientation or gender identity
• the types of practices used tend to be similar (for example, talking therapies delivered by faith groups or mental health professionals)
• conversion therapies were associated with self-reported harms (such as mental health conditions like depression and feeling suicidal) in both sets of study participants

The only real difference in the evidence base for conversion therapy for sexual orientation and gender identity is that there is more evidence on sexual orientation because it has been studied for longer.

6. Conversion therapy for sexual orientation

The evidence on conversion therapy for sexual orientation comes from 41 studies:

• 33 from the USA
• 2 from South Africa
• 1 from each of Canada, China, Poland and the UK
• 2 systematic reviews of international evidence

Overall the largest proportion of studies were assessed as being of average or below average quality. The qualitative studies were assessed as being of higher quality due to the nature of the research topic. More rigorous quantitative studies of conversion therapy are hampered by the methodological challenges already discussed, meaning that the majority are based on self-reported evidence.

The majority of studies concentrated on participants’ experiences of conversion therapy and the outcomes of conversion therapy.

Studies relating to conversion therapy for sexual orientation show that:

• there is no robust evidence that conversion therapy can change sexual orientation
• conversion therapy tended to be delivered by faith groups and mental health professionals and tended to use talking therapies
• there is consistent evidence of self-reported harms, such as negative mental health effects like depression and feeling suicidal
• people’s motivations for seeking conversion therapy tended to be associated with conflict about sexual orientation

Given that there are more studies into conversion therapy for sexual orientation, there are fewer gaps. However, little evidence was found about the experiences of women and people from ethnic minority groups undergoing conversion therapy. Some studies included samples from these populations, but they were smaller compared with those for men from White ethnic groups. No studies were found which were based on the experiences of these groups specifically. As a result, we do not know whether and how their experiences might differ.

7. Conversion therapy for gender identity

The main evidence on conversion therapy for gender identity comes from 4 studies:

• 3 from the USA
• 1 systematic review of international evidence

There was no specific evidence focusing exclusively on conversion therapy for gender identity in the UK.

In general, the research from the USA was assessed as being of above average quality using the MMAT system. It consisted of 2 studies which analysed data from the large-scale Transgender Survey 2015, and a study which tested perceptions of different therapies (including non-affirming responses by therapists of gender identity) among 400 transgender participants. The systematic review is a robust study of the available evidence on conversion therapy for gender identity, and access to transition-related healthcare in transgender people. However, it is limited by the lack of studies in this area to review.

In addition, the National LGBT Survey provides a snapshot estimate on the scale of conversion therapy among transgender respondents in the UK. The survey found that 13% of transgender respondents had been offered some form of conversion therapy for either sexual orientation or gender identity.

Studies relating to conversion therapy for gender identity and transgender participants show that:

• there is no robust evidence that conversion therapy can change gender identity
• the types of practices used tend to be similar to those for conversion therapy for sexual orientation
• there was some robust evidence of self-reported harms (such as negative mental health effects like depression and feeling suicidal)
• there was indicative evidence that transgender respondents were as likely or more likely to be offered and receive conversion therapy than non-transgender respondents

Compared with conversion therapy for sexual orientation, little evidence was found on the detailed experiences of people who have gone through conversion therapy for gender identity, specifically in the UK (such as duration, frequency, and modalities and characteristics of approaches). There is also little evidence about the paths people have taken towards conversion therapy (for example, how voluntary and involuntary they were) and their subsequent experiences.

8. Conclusion

This assessment looked at the nature, quality and quantity of evidence on conversion therapy to change sexual orientation and gender identity exclusively. It found that the evidence base for conversion therapy for sexual orientation is long-established, extending over 20 years, while for gender identity the evidence base is newer. Despite being fewer in number, studies looking at conversion therapy for gender identity were assessed as being stronger in design than those for sexual orientation. This is largely due to their larger sample sizes which can help to reduce sampling limitations.

This assessment also found that research on conversion therapy is affected by methodological challenges. This limits the ability to say definitively what the impact of conversion therapy is. However, this report notes that the quality of evidence identified in this assessment is the highest that is achievable. While the evidence is predominantly based on self-reporting, consistent patterns were found which enable indicative conclusions to be found. These are that there is no robust evidence that conversion therapy can change sexual orientation or gender identity, and that conversion therapy is frequently associated with harm.

9. References

Government Equalities Office (2018). ‘National LGBT Survey: Research report’. Government Equalities Office.

Jowett A, Brady G, Goodman S, Pillinger C and Bradley (2021), ‘Conversion Therapy: An evidence assessment and qualitative study’. Government Equalities Office.

Pluye P, Gagnon MP, Griffiths F, and Johnson-Lafleur J (2009), ‘A scoring system for appraising mixed methods research, and concomitantly appraising qualitative, quantitative and mixed methods primary studies in Mixed Studies Reviews’. International journal of nursing studies. 46. 529-46. 10.1016/j.ijnurstu.2009.01.009.

10. Appendix 1. List of studies reviewed

American Psychological Association (2009). ‘Report of the Task Force on Appropriate Therapeutic Responses to Sexual Orientation’. American Psychological Association

Arthur E, McGill D and Essary E H (2014). Playing it straight: Framing strategies among reparative therapists. Sociological Inquiry, 84(1), 16-41. Available at: https://doi.org/10.1111/soin.12026

Bartlett A, Smith G and King M (2009). The response of mental health professionals to clients seeking help to change or redirect same-sex sexual orientation. BMC Psychiatry, 9(1), 11. Available at: https://doi.org/10.1186/1471-244X-9-11

Beckstead A L (2002). Cures versus choices: Agendas in sexual reorientation therapy Journal of Gay and Lesbian Psychotherapy, 5(3-4), 87-115. Available at: https://doi.org/10.1300/J236v05n03_07

Beckstead A L and Morrow S L (2004). Mormon clients’ experiences of conversion therapy: The need for a new treatment approach. The Counseling Psychologist, 32(5), 651-690. Available at: https://doi.org/10.1177/0011000004267555

Bettergarcia J N and Israel T. (2018). Therapist reactions to transgender identity exploration: Effects on the therapeutic relationship in an analogue study. Psychology of Sexual Orientation and Gender Diversity, 5(4), 423.

Blosnich J R, Henderson E R, Coulter R W, Goldbach J T and Meyer I H (2020). Sexual Orientation Change Efforts, Adverse Childhood Experiences, and Suicide Ideation and Attempts among Sexual Minority Adults, United States, 2016–2018. American journal of public health, (0), e1-e7.

Boland E. (2005). Ex Exodus. Journal of Bisexuality, 5(2-3), 247-254.

Borowich A E (2008). Failed reparative therapy of Orthodox Jewish homosexuals. Journal of Gay and Lesbian Mental Health, 12(3), 167-177. Available at: https://doi.org/10.1080/19359700802111072

Bradshaw K, Dehlin J P, Crowell K A, Galliher R V and Bradshaw W S (2015). Sexual orientation change efforts through psychotherapy for LGBQ individuals affiliated with the Church of Jesus Christ of Latter-day Saints. Journal of Sex and Marital Therapy, 41(4), 391-412. Available at: https://doi.org/10.1080/0092623X.2014.915907

Byrd D A, Nicolosi J and Potts R W (2008). Clients’ perceptions of how reorientation therapy and self-help can promote changes in sexual orientation. Psychological reports, 102(1), 3-28.

Dehlin J P, Galliher R V, Bradshaw W S, Hyde D C and Crowell K A (2015). Sexual orientation change efforts among current or former LDS church members. Journal of Counseling Psychology, 62(2), 95. Available at: https://doi.org/10.1037/cou0000011

Fjelstrom J (2013). Sexual orientation change efforts and the search for authenticity. Journal of Homosexuality, 60(6), 801-827. Available at: https://doi.org/10.1080/00918369.2013.774830

Flentje A, Heck N C and Cochran B N (2013). Sexual reorientation therapy interventions: Perspectives of ex-ex-gay individuals. Journal of Gay and Lesbian Mental Health, 17(3), 256-277. https://doi.org/10.1080/19359705.2013.773268

Flentje A, Heck N C and Cochran B N (2014). Experiences of ex-ex-gay individuals in sexual reorientation therapy: Reasons for seeking treatment, perceived helpfulness and harmfulness of treatment, and post-treatment identification. Journal of Homosexuality, 61(9), 1242-1268. https://doi.org/10.1080/00918369.2014.926763

Ford J G (2002). Healing homosexuals: A psychologist’s journey through the ex-gay movement and the pseudo-science of reparative therapy. Journal of Gay and Lesbian Psychotherapy, 5(3-4), 69-86.

Government Equalities Office (2018). National LGBT Survey: Research report. Government Equalities Office.

Haldeman D C (2002). Therapeutic antidotes: Helping gay and bisexual men recover from conversion therapies. Journal of Gay and Lesbian Psychotherapy, 5(3-4), 117-130.

Johnston L B and Jenkins D (2006). Lesbians and gay men embrace their sexual orientation after conversion therapy and ex-gay ministries: A qualitative study. Social Work in Mental Health, 4(3), 61-82. Available at: https://doi.org/10.1300/J200v04n03_04

Karten E Y and Wade J C (2010). Sexual orientation change efforts in men: A client perspective. The Journal of Men’s Studies, 18(1), 84-102. Available at: https://doi.org/10.3149/jms.1801.84

Maccio E M (2010). Influence of family, religion, and social conformity on client participation in sexual reorientation therapy. Journal of Homosexuality, 57(3), 441-458. Available at: https://doi.org/10.1080/00918360903543196

Maccio E M (2011). Self-reported sexual orientation and identity before and after sexual reorientation therapy. Journal of Gay and Lesbian Mental Health, 15(3), 242-259.

Meanley S P, Stall R D, Dakwar O, Egan J E, Friedman M R, Haberlen S A and Plankey M W (2020). Characterizing experiences of conversion therapy among middle-aged and older men who have sex with men from the Multi center AIDS Cohort Study (MACS). Sexuality Research and Social Policy, 17(2), 334-342.

Meanley S, Haberlen S A, Okafor C N, Brown A, Brennan-Ing M, Ware D and Plankey M W (2020). Lifetime Exposure to Conversion Therapy and Psychosocial Health among Midlife and Older Adult Men Who Have Sex with Men. The Gerontologist.

Meyer W S (2013). Part 2: Homosexuality Uncured: Reflections of a Former Analysand. Smith College Studies in Social Work, 83(1), 36-44.

Mikulak M. (2020). Telling a poor man he can become rich: Reparative therapy in contemporary Poland. Sexualities, 23(1-2), 44-63.

Nicolosi J, Byrd A D and Potts R W (2000). Beliefs and practices of therapists who practice sexual reorientation psychotherapy. Psychological Reports, 86(2), 689-702. Available at: https://doi.org/10.2466/pr0.2000.86.2.689

Nicolosi J, Byrd A D and Potts R W (2000). Retrospective self-reports of changes in homosexual orientation: A consumer survey of conversion therapy clients. Psychological Reports, 86(3), 1071-1088. Available at: https://doi.org/10.2466/pr0.2000.86.3c.1071

Robinson C M and Spivey S E (2019). Ungodly Genders: Deconstructing Ex-Gay Movement Discourses of “Transgenderism” in the US. Social Sciences, 8(6), 191.

Ryan C, Toomey R B, Diaz R M and Russell S T (2018). Parent-initiated sexual orientation change efforts with LGBT adolescents: Implications for young adult mental health and adjustment. Journal of Homosexuality, 67(2), 159-173. Available at: https://doi.org/10.1080/00918369.2018.1538407

Salway T, Ferlatte O, Gesink D and Lachowsky N J (2020). Prevalence of exposure to sexual orientation change efforts and associated sociodemographic characteristics and psychosocial health outcomes among Canadian sexual minority men. The Canadian Journal of Psychiatry, 0706743720902629.

Santero P L, Whitehead N E and Ballesteros D. (2018). Effects of therapy on religious men who have unwanted same-sex attraction. The Linacre Quarterly. Available at: https://doi.org/10.1177/0024363918788559 (Retraction published 2020, The Linacre Quarterly, 87(1) 108. Available at: https://doi.org/10.1177/0024363919854842)

Schroeder M and Shidlo A (2002). Ethical issues in sexual orientation conversion therapies: An empirical study of consumers. Journal of Gay and Lesbian Psychotherapy, 5(3-4), 131-166. Available at: https://doi.org/10.1300/J236v05n03_09

Serovich J M, Craft S M, Toviessi P, Gangamma R, McDowell T and Grafsky E L (2008). A systematic review of the research base on sexual reorientation therapies. Journal of Marital and Family Therapy, 34(2), 227-238. Available at: https://doi.org/10.1111/j.1752-0606.2008.00065.x

Shidlo A and Schroeder M (2002). Changing sexual orientation: A consumers’ report.Professional Psychology: Research and Practice, 33(3), 249. Available at: https://doi.org/10.1037/0735-7028.33.3.249

Spitzer R L (2003). Can some gay men and lesbians change their sexual orientation? 200 participants reporting a change from homosexual to heterosexual orientation. Archives of Sexual Behavior, 32(5), 403-417. Available at: https://doi.org/10.1023/A:1025647527010

Suen Y T and Chan R C H (2020). A nationwide cross-sectional study of 15,611 lesbian, gay and bisexual people in China: disclosure of sexual orientation and experiences of negative treatment in health care. International Journal for Equity in Health, 19, 1-12.

Throckmorton W and Welton G (2005). Counseling practices as they relate to ratings of helpfulness by consumers of sexual reorientation therapy. Journal of Psychology and Christianity, 24(4), 332.

Tozer E E and Hayes J A (2004). Why do individuals seek conversion therapy? The role of religiosity, internalized homonegativity, and identity development. The Counseling Psychologist, 32(5), 716-740. Available at: https://doi.org/10.1177/0011000004267563

Turban J L, Beckwith N, Reisner S L and Keuroghlian A S (2020). Association between recalled exposure to gender identity conversion efforts and psychological distress and suicide attempts among transgender adults. Jama Psychiatry, 77(1), 68-76.

Turban J L, King D, Reisner S L and Keuroghlian A S (2019). Psychological attempts to change a person’s gender identity from transgender to cisgender: estimated prevalence across US States, 2015. American journal of public health, 109(10), 1452-1454.

Van Zyl, J, Nel K and Govender S. (2017). Reparative sexual orientation therapy effects on gay sexual identities. Journal of Psychology in Africa, 27(2), 191-197. Available at: https://doi.org/10.1080/14330237.2017.1303126

Van Zyl J, Nel K and Govender S. (2018). Gender identity issues in pastoral reparative therapy in the Nederduitse Gereformeerde Kerk (NGK), South Africa. Gender and Behaviour, 16(1), 10668-10676.

Weiss E M, Morehouse J, Yeager T and Berry T. (2010). A qualitative study of ex-gay and ex-ex-gay experiences. Journal of Gay and Lesbian Mental Health, 14(4), 291-319. Available at: https://doi.org/10.1080/19359705.2010.506412

Wolkomir M. (2001). Emotion work, commitment, and the authentication of the self: The case of gay and ex-gay Christian support groups. Journal of Contemporary Ethnography, 30(3), 305-334. Available at: https://doi.org/10.1177/089124101030003002

Wright T, Candy B and King M (2018). Conversion therapies and access to transition-related healthcare in transgender people: a narrative systematic review. BMJ Open, 8(12), e022425. Available at: https://doi.org//10.1136/bmjopen-2018-022425

11. Appendix 2. Summary findings from assessment of conversion therapy studies

	Sexual orientation (41 studies since 2000)	Gender identity (4 studies since 2018)	National LGBT Survey 2017
Geography	33 studies from the USA 2 from South Africa 1 each from Canada, China, Poland and the UK 2 systematic reviews of international evidence	3 studies from the USA 1 systematic review of international evidence	1 study from the UK
Method	20 qualitative studies 19 quantitative studies 2 systematic reviews	3 quantitative studies, which include: 2 studies based on the Transgender Survey 2015, a non-random survey with of 28,000 transgender people in the USA, which explicitly covers conversion therapy for gender identity 1 study which tested perceptions of different therapy (including non-affirming responses by therapists of gender identity) among 400 transgender participants 1 systematic review	Non-random survey with approximately 108,000 LGBT respondents in the UK which identifies characteristics of those who have experienced or been offered conversion therapy Experience of conversion therapy may have related to at sexual orientation or gender identity
Quality	Majority of studies were assessed as being of average, or below average quality Majority of qualitative studies were assessed as being of average or above average quality Majority of quantitative studies were assessed as being average or below average quality, hampered by design	All studies assessed as being of above average quality	Assessed as being of average quality
Topic	Participants’ experiences of conversion therapy The outcomes of conversion therapy	Scale of conversion therapy for gender identity among transgender people Participants’ experiences of conversion therapy The outcomes of conversion therapy	Indicative estimate of scale of conversion therapy, among which groups, and who delivered it in the UK
Summary of findings	No robust evidence that conversion therapy can change sexual orientation Tended to be delivered by faith groups and mental health professionals and tended to use talking therapies Consistent evidence of self-reported harms (such as negative mental health effects like depression and suicidality) associated with conversion therapy People’s motivations for seeking conversion therapy tended to be associated with conflict about sexual orientation	No robust evidence that conversion therapy can change gender identity. Some evidence that therapy tended to use talking therapies Some robust evidence of self-reported harms (such as negative mental health effects like depression and suicidality) associated with conversion therapy Some evidence that transgender respondents are more likely to be offered and receive conversion therapy than non-transgender respondents	Transgender respondents more likely to be offered and receive conversion therapy than non-transgender respondents Limited but robust evidence from the UK tells us that approaches tended to be delivered by faith groups, health professionals or family members