Guidance

Climate change and mental health: people with existing conditions

Those with pre-existing health conditions may be at increased risk of mental health impacts associated with extreme weather.

• From: UK Health Security Agency and Centre for Climate and Health Security
• Published: 12 November 2025

Applies to England

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Topic: health impacts
Part of: Climate change and mental health

Key mental health resources to support people with existing conditions:

• Climate change and mental health: people with existing conditions

• Overview of the climate change and mental health report

• Climate change and mental health report (pdf)

• Mental health medications and extreme weather

• Why some people suffer more than others during heatwaves

Additional resources:

• Don’t let the heatwave affect your medicines: Three important tips from the MHRA

• Hot Weather Health Plan – Society for Acute Medicine

• Deep Adaptation Forum

• The importance of teaching climate-health literacy in psychotherapeutic training and continuing education

The impact on those with existing health conditions

The climate change and mental health report found evidence that people with existing mental health conditions face significantly higher risks during extreme heat events, with higher risk of mortality compared to the general population.

This vulnerability is partly due to psychotropic medications (those that affect brain function, alter mood, behavior, thoughts and perception) that can impair temperature regulation, and cognitive difficulties that can make recognising heat stress symptoms more difficult.

For dementia patients in particular, there can be increases in agitation and hospital admissions with rising temperatures, An English study found that for every 1°C rise in temperature above 17°C there was a 4.5% increase risk of dementia-related hospital admissions (1). Inflammation within the brain from heat stress may also worsen conditions like depression and psychosis.

Environmental disasters such as floods and wildfires increase mental health risks, especially for those with pre-existing conditions. Flooding has been linked to increased suicide risk amongst those who suffer from post-traumatic stress disorder (PTSD), and worsened psychological health for individuals with poor physical health (2).

Disruptions to healthcare access and communication barriers for people with disabilities can intensify these effects. Similarly, wildfires and smoke exposure have been shown to raise the risk of PTSD, anxiety, and depression, particularly among those with prior mental health issues or financial stress. Adolescents with previous trauma also exhibit more severe symptoms after a disaster.

Individuals with physical health difficulties may also be at increased risk of mental health impacts from flooding. For example, disruptions to health services and support during and following a flood event are likely to affect those with pre-existing health conditions the most, which may contribute to this higher risk of mental health impacts. People with disabilities have also reported communication barriers with accessing health and community services after experiencing flooding.

References

1. Gong J, and others. ‘Current and future burdens of heat-related dementia hospital admissions in England’ Environment International 2022: volume 159

2. Zhong S, and others. ‘The long-term physical and psychological health impacts of flooding: A systematic mapping’ Science of the Total Environment 2018: volume 626 pages 165 to 194

Published 12 November 2025