Risk factors for mental health conditions include adverse childhood experiences, genetics, psychological vulnerabilities, environmental factors (e.g., malnutrition, poor air quality), stressful life events, family and community dynamics, and structural factors (e.g., poverty, education, inequality).

People with mental health conditions often face a host of challenges, such as physical health problems, limited job opportunities, low income, unaffordable housing, stigma, and barriers to access health care, which can create cycles of disadvantage that are difficult to break. What’s more, health care systems are not adequately responding to the needs of people with mental health disorders. This treatment gap is widest in low and middle income countries, where around 3 out of 4 people with a mental health condition do not receive the care, treatment, or support they need.

Climate change is profoundly impacting mental health across the world through dangerous and damaging extreme weather events, displacement, economic instability, and limiting access to care. Individuals already grappling with mental health conditions are disproportionately impacted due to the pre-existing challenges they live with.

• exacerbation of existing mental health symptoms,
• development of new mental health symptoms,
• increased emergency room admissions, and
• increased risk of death (mortality) and illness or disease (morbidity).

This research has been affirmed by the World Health Organization (WHO), which has identified “pre-existing mental health conditions” as a vulnerability factor for climate-related mental health impacts. 

Factors contributing to this increased vulnerability to climate impacts, such as extreme weather events, may include: reduced ability to regulate their body temperatures (thermoregulation), mental health medication affecting thermoregulation, social isolation, limited awareness of health risks, and the links between mental health disorders and inadequate housing or homelessness and physical health problems. 

Extreme weather events driven by climate change also disrupt mental health care systems, affecting facilities, services, and community-based support networks. These disruptions widen the already large treatment gap between people in need of mental health care and those who are able to access it. 

HEAT EVENTS: are defined as exposure to a high mean temperature in a single day, or prolonged exposure to high temperatures over multiple days (heat waves). Heat can negatively impact everyone’s mental health, but in general, following exposure to heat events, people with pre-existing mental health conditions, compared to those without, are more likely to die, experience heat stroke, and experience worsening of existing mental health symptoms. 

• Depression: People with depression face a higher risk of mortality during high air temperatures compared to those without. For instance, during a heatwave in Chicago in the United States, people diagnosed with depression were four times at higher risk of death than people without depression. Similarly, in Italy, another investigation revealed an increased mortality risk among participants with depression at temperatures of 30°C compared to 20°C.
• Schizophrenia: Following exposure to high temperatures, people with schizophrenia are more likely to experience heatstroke and other heat-related illness and death and exacerbation of symptoms, measured by increased hospital admissions. The risk is higher when they have accompanying co-morbidities (which means another health problem on top of the main diagnosis). In the 2021 heat dome event that affected British Columbia, 309 people living with schizophrenia died. This is a three-fold increase in deaths during the heat dome compared to deaths during the same period in previous years. The risk of death for people with schizophrenia was larger than for any other chronic illness. Reasons for worse health outcomes among people with schizophrenia include:
  • their medication may exacerbate heat illness,
  • they are more likely to suffer chronic physical conditions like diabetes, which is a risk factor for heat-related illness,
  • symptoms might impair their comprehensive of the risk of heat, and
  • they often experience social isolation and withdrawal, which limits their ability to seek help during heat events.
• People with dementia and substance misuse may have a higher risk of death following heat events, but research results are mixed. 
• Obsessive-compulsive disorder (OCD): One study has found that hot weather exacerbated symptoms of OCD, but this is an area with very little research. 

FLOODS: The repercussions of floods extend far beyond the event itself – displacement from homes, loss of belongings, and disruption of daily routines exacerbate the stress experienced by individuals with mental health conditions. The impacts of floods have been studied by assessing mental health before and after a flood, but longer-term impacts (years after) are not always considered. 

• Depression: Some studies show the risk for mental health problems for individuals with pre-existing depression was high in different timeframes following a flood, such as ten days, two to three months, and even nine months after the flood. 
• Anxiety: Some studies indicate that five months after a flood, women with pre-existing anxiety, have a 2.85-times-higher risk of depression, a 7.07-times-higher risk of anxiety, and a 2.49-times-higher risk of PTSD compared to women without pre-existing anxiety.

WILDFIRES: Evacuation orders, uncertainty about the safety of homes and loved ones, and the loss of property can greatly elevate stress levels and trigger distressing emotions. Smoke and haze from wildfires can exacerbate respiratory conditions and contribute to an overall sense of unease and discomfort.

• Depression: Individuals with a history of depression have been shown to be significantly more likely to develop PTSD following wildfires across Australia, Canada, and the United States, compared to those without a history of depression. Some studies indicate that people with pre-existing depression have a higher risk of developing depression and anxiety following wildfires, while others show no increased risk.
• Anxiety: Some people living with anxiety can face a 5.13-times-higher risk of developing depression compared to those without pre-existing anxiety six months after a wildfire, although some studies report no increased risk at 18 months post-wildfire. Researchers also found that people with pre-existing anxiety can have a significantly higher risk of PTSD at 6 and 18 months after a wildfire event.

HURRICANES: Catastrophic events such as hurricanes have a significant impact on individuals living with mental health conditions.

• Post-traumatic stress disorder (PTSD): Individuals affected by Hurricane Sandy in New York City were more likely to report PTSD symptoms if they had a prior history of 9/11 related PTSD symptoms. 
• Attention-deficit hyperactivity disorder (ADHD): One study found that children living with ADHD were 365% more likely to be diagnosed with PTSD up to 28 months after Hurricane Katrina in New Orleans compared to children with other mental health issues, excluding ADHD.

People with pre-existing mental health conditions may experience climate impacts differently, depending on symptom characteristics and severity, the strength of their social and community support networks, comorbid physical disabilities, and demographic or socioeconomic variables like age, sex, race, geographic location, and economic status. 

• Existing inequalities: People with pre-existing mental health conditions may face stigma and discrimination, limited employment opportunities, and difficulty accessing key services and support, all of which can be exacerbated by climate impacts. 
• Relationship with poverty: People who experience low income, unemployment, social exclusion and/or housing insecurity or homelessness are more likely to have mental illness. People with socioeconomically disadvantaged backgrounds often face limited access to resources, healthcare, and social support systems, which are exacerbated by climate impacts like economic instability, loss of home and displacement.
• Children with emotional, behavioural, or cognitive challenges are especially vulnerable due to their developing bodies and minds. Exposure to extreme weather conditions, environmental degradation, and displacement can lead to heightened anxiety, behavioral disturbances, and trauma. Disruptions in education, social networks, and family stability can impact and exacerbate mental health challenges. A majority of mental health conditions first emerge in early adolescence around 14.5 years of age. Exposure to trauma, instability, or disruptions in early life can influence outcomes throughout childhood and into adulthood. 
• Geographic disparities: Availability and accessibility of mental health services are inadequate around the world, but they are lacking or even non-existent in low-income countries, compared to wealthier countries, and stigma is a major barrier to help-seeking in people with mental health difficulties in developing countries. At the same time, many low-income countries are the most vulnerable to climate impacts like extreme heat and sea level rise.

1. Ensure that mental health services and treatments including medications, counseling, therapy sessions, support groups, and hotlines staffed by trained mental health professionals are accessible and culturally-relevant, and remain so during crises like extreme weather events. Research shows that many therapists are confronted with climate change-related concerns and regard the mental health impact of climate change on their patients as meaningful to care.

2. Increase education and awareness about the psychological effects of climate change through increased training and upskilling to doctors and mental health professionals and helping people in community settings build skills to support each other. These initiatives should communicate risks, available resources, prevention strategies, and guidance on recognizing and responding to warnings and emergencies. Such efforts can help reduce stigma, increase understanding, and encourage individuals living with existing mental health conditions to seek support.

3. Address social determinants of health: Recognize that socioeconomic and structural factors play a significant role in shaping mental health outcomes. Addressing issues such as poverty, inequality, racism, and limited access to healthcare is essential to mitigating the mental health impacts of climate change. In this context, measures such as ensuring access to air conditioning or public cooling centers during heatwaves for people experiencing homelessness, providing clean drinking water for hydration in under-resourced countries, and deploying mobile health clinics in rural areas can make a meaningful difference.

4. Advocate for policies that prioritize mental health in climate change adaptation and mitigation efforts. This could include integrating mental health considerations into disaster preparedness plans, investing in mental health research, and developing protocols and systems for mental health support during and after climate-related disasters. This may involve collaboration between mental health professionals, emergency responders, and community organizations.

5. Provide adequate funding for mental health services. Governments and international climate financing must address the already wide gap between people’s needs for mental health care and the system’s ability to provide it.

6. Implement community-based approaches to reduce vulnerability. For example, mental health care teams can proactively identify and support at-risk patients before and during extreme weather events by reaching out regularly to check on their well-being, offering timely help, and providing resources such as a list of public Resilience Hubs in clinical settings.

• There is a lack of data on mental health conditions, especially in low- and middle-income countries, partly due to people’s reluctance to seek help because of the stigma and discrimination.
• Medications for mental health conditions are an important risk factor for climate risks. Certain medications affect thermoregulation, hydration, and cognitive responsiveness to environmental stressors.
• Certain individuals may be more vulnerable to climate stressors due to psychological factors, such as heightened sensitivity to stress, difficulty coping with changes, or reliance on routine for stability.
• Environmental factors associated with climate change, such as air pollution or wildfire smoke, may act as triggers for symptoms of mental illness in individuals at-risk. Understanding these interactions is crucial for developing interventions.
• Research on mental health conditions is challenging because of the diversity of symptoms that individuals experience – many clinicians and researchers consider diagnoses on a spectrum, rather than discrete categories.

Spinning out: Climate Change, Mental Health and Fighting for a Better Future by Charlie Hertzog-Young, published in 2023 by Footnote Press.

Climate change and mental health: How extreme heat can affect mental illnesses, published in The Conversation on May 28, 2024, by Peter Crank.

Explained: How climate change affects mental health, published in Wellcome Trust on November 7, 2023, by Alessandro Massazza

Global Study Exposes Critical Data Gaps in Mental Health Prevalence-Children and Low-Income Countries Most Affected, published in Rehabilitation International on May 9, 2025

No One Left Behind, published in Money and Mental Health Policy Institute: London, UK, in July, 2022 by Becca Stacey and Conor D’Arcy.

Over a billion people living with mental health conditions – services require urgent scale-up, published in World Health Organization News on September 2, 2025.

Agyapong, V.I.O., Juhas, M., Omege, J. et al. Prevalence Rates and Correlates of Likely Post-Traumatic Stress Disorder in Residents of Fort McMurray 6 Months After a Wildfire. Int J Ment Health Addiction 19, 632–650 (2021). https://doi.org/10.1007/s11469-019-00096-z

Agyapong, V. I. O., Ritchie, A., Brown, M. R. G., Noble, S., Mankowsi, M., Denga, E., Nwaka, B., Akinjise, I., Corbett, S. E., Moosavi, S., Chue, P., Li, X. M., Silverstone, P. H., & Greenshaw, A. J. (2020). Long-Term Mental Health Effects of a Devastating Wildfire Are Amplified by Socio-Demographic and Clinical Antecedents in Elementary and High School Staff. Frontiers in psychiatry, 11, 448. https://doi.org/10.3389/fpsyt.2020.00448 

Airhia, E.E. (2015). Predicting Post Traumatic Stress Disorder in Children with Prior Mental Health Diagnoses.

Berry, H.L.; Waite, T.D.; Dear, K.B.G.; Capon, A.G.; Murray, V. The case for systems thinking about climate change and mental health. Nature. Clim. Change. 2018, 8, 282–290. https://doi.org/10.1038/s41558-018-0102-4 

Brierley, M. E., Albertella, L., do Rosário, M. C., Ferrão, Y. A., Miguel, E. C., & Fontenelle, L. F. (2021). How do daily routines and situational factors affect the severity of obsessive-compulsive disorder?. Journal of psychiatric research, 143, 395–399. https://doi.org/10.1016/j.jpsychires.2021.09.040 

Caramanica, K., Brackbill, R. M., Stellman, S. D., & Farfel, M. R. (2015). Posttraumatic Stress Disorder after Hurricane Sandy among Persons Exposed to the 9/11 Disaster. International journal of emergency mental health, 17(1), 356–362. https://doi.org/10.4172/1522-4821.1000173 

Casella, C. B., Kousoulis, A. A., Kohrt, B. A., Bantjes, J., Kieling, C., Cuijpers, P., Kline, S., Kotsis, K., Polanczyk, G. V., Stein, D. J., Szatmari, P., Merikangas, K. R., Mneimneh, Z., & Salum, G. A. (2025). Data gaps in prevalence rates of mental health conditions around the world: a retrospective analysis of nationally representative data. The Lancet. Global health, 13(5), e879–e887. https://doi.org/10.1016/S2214-109X(24)00563-1

Crank, P. J., Hondula, D. M., & Sailor, D. J. (2023). Mental health and air temperature: Attributable risk analysis for schizophrenia hospital admissions in arid urban climates. The Science of the total environment, 862, 160599. https://doi.org/10.1016/j.scitotenv.2022.160599

Eissa, M., Newberry Le Vay, J., Jennings, N., Lawrance, E.L., Massazza, A., Integrating Mental Health into Climate Change Adaptation Policies (2025), United for Global Mental Health.

Felton, J. W., Cole, D. A., & Martin, N. C. (2013). Effects of rumination on child and adolescent depressive reactions to a natural disaster: the 2010 Nashville flood. Journal of abnormal psychology, 122(1), 64–73. https://doi.org/10.1037/a0029303 

Hayes, J., Mason, J., Brown, F., & Mather, R. (2009). Floods in 2007 and older adult services: lessons learnt. Psychiatric Bulletin, 33(9), 332–336. https://doi.org/10.1192/pb.bp.108.021261  

Hetherington, E., McDonald, S., Wu, M., & Tough, S. (2018). Risk and Protective Factors for Mental Health and Community Cohesion After the 2013 Calgary Flood. Disaster medicine and public health preparedness, 12(4), 470–477. https://doi.org/10.1017/dmp.2017.91 

Hoffmann, M. S., Oliveira, L. M., Lobato, M. I., & Belmonte-de-Abreu, P. (2016). Heat stroke during long-term clozapine treatment: should we be concerned about hot weather?. Trends in psychiatry and psychotherapy, 38(1), 56–59. https://doi.org/10.1590/2237-6089-2015-0066 

Hoffman, Stacey J, “Coping processes of Midwest flood survivors: A comparison of those with and without prior natural disaster exposure” (2006). ETD collection for University of Nebraska-Lincoln. AAI3217587. https://digitalcommons.unl.edu/dissertations/AAI3217587 

Isaac, F., Toukhsati, S. R., Klein, B., Di Benedetto, M., & Kennedy, G. A. (2024). Pre-existing depression, anxiety and trauma as risk factors for the development of post-traumatic stress disorder symptoms following wildfires. Psychiatry Research Communications, 4(2), 100161. https://doi.org/10.1016/j.psycom.2024.100161   

Kao, R. L., & Kelly, L. M. (2007). Fatal exertional heat stroke in a patient receiving zuclopenthixol, quetiapine and benztropine. The Canadian journal of clinical pharmacology = Journal canadien de pharmacologie clinique, 14(3), e322–e325.

Kirkbride, J. B., Anglin, D. M., Colman, I., Dykxhoorn, J., Jones, P. B., Patalay, P., Pitman, A., Soneson, E., Steare, T., Wright, T., & Griffiths, S. L. (2024). The social determinants of mental health and disorder: evidence, prevention and recommendations. World psychiatry : official journal of the World Psychiatric Association (WPA), 23(1), 58–90. https://doi.org/10.1002/wps.21160

Kwok, J. S., & Chan, T. Y. (2005). Recurrent heat-related illnesses during antipsychotic treatment. The Annals of pharmacotherapy, 39(11), 1940–1942. https://doi.org/10.1345/aph.1G130 

Lee, C. P., Chen, P. J., & Chang, C. M. (2015). Heat stroke during treatment with olanzapine, trihexyphenidyl, and trazodone in a patient with schizophrenia. Acta neuropsychiatrica, 27(6), 380–385. https://doi.org/10.1017/neu.2015.29 

Lee, M. J., McLean, K. E., Kuo, M., Richardson, G. R. A., & Henderson, S. B. (2023). Chronic Diseases Associated With Mortality in British Columbia, Canada During the 2021 Western North America Extreme Heat Event. GeoHealth, 7(3). https://doi.org/10.1029/2022gh000729

Martin, N. C., Felton, J. W., & Cole, D. A. (2016). Predictors of Youths’ Posttraumatic Stress Symptoms Following a Natural Disaster: The 2010 Nashville, Tennessee, Flood. Journal of clinical child and adolescent psychology: the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53, 45(3), 335–347. https://doi.org/10.1080/15374416.2014.982279 

Meadows, J., Mansour, A., Gatto, M. R., Li, A., Howard, A., & Bentley, R. (2024). Mental illness and increased vulnerability to negative health effects from extreme heat events: a systematic review. Psychiatry research, 332, 115678. https://doi.org/10.1016/j.psychres.2023.115678

Moosavi, S., Nwaka, B., Akinjise, I., Corbett, S. E., Chue, P., Greenshaw, A. J., Silverstone, P. H., Li, X. M., & Agyapong, V. I. O. (2019). Mental Health Effects in Primary Care Patients 18 Months After a Major Wildfire in Fort McMurray: Risk Increased by Social Demographic Issues, Clinical Antecedents, and Degree of Fire Exposure. Frontiers in psychiatry, 10, 683. https://doi.org/10.3389/fpsyt.2019.00683 

Naughton, M. P., Henderson, A., Mirabelli, M. C., Kaiser, R., Wilhelm, J. L., Kieszak, S. M., Rubin, C. H., & McGeehin, M. A. (2002). Heat-related mortality during a 1999 heat wave in Chicago. American journal of preventive medicine, 22(4), 221–227. https://doi.org/10.1016/s0749-3797(02)00421-x 

Page, L. A., Hajat, S., Kovats, R. S., & Howard, L. M. (2012). Temperature-related deaths in people with psychosis, dementia and substance misuse. The British journal of psychiatry : the journal of mental science, 200(6), 485–490. https://doi.org/10.1192/bjp.bp.111.100404 

Rathod, S., Pinninti, N., Irfan, M., Gorczynski, P., Rathod, P., Gega, L., & Naeem, F. (2017). Mental Health Service Provision in Low- and Middle-Income Countries. Health services insights, 10, 1178632917694350. https://doi.org/10.1177/1178632917694350

Solmi, M., Radua, J., Olivola, M. et al. Age at onset of mental disorders worldwide: large-scale meta-analysis of 192 epidemiological studies. Mol Psychiatry 27, 281–295 (2022). https://doi.org/10.1038/s41380-021-01161-7

Stafoggia, M., Forastiere, F., Agostini, D., Biggeri, A., Bisanti, L., Cadum, E., Caranci, N., de’ Donato, F., De Lisio, S., De Maria, M., Michelozzi, P., Miglio, R., Pandolfi, P., Picciotto, S., Rognoni, M., Russo, A., Scarnato, C., & Perucci, C. A. (2006). Vulnerability to heat-related mortality: a multicity, population-based, case-crossover analysis. Epidemiology (Cambridge, Mass.), 17(3), 315–323. https://doi.org/10.1097/01.ede.0000208477.36665.34 

Stivanello, E., Chierzi, F., Marzaroli, P., Zanella, S., Miglio, R., Biavati, P., Perlangeli, V., Berardi, D., Fioritti, A., & Pandolfi, P. (2020). Mental Health Disorders and Summer Temperature-Related Mortality: A Case Crossover Study. International journal of environmental research and public health, 17(23), 9122. https://doi.org/10.3390/ijerph17239122 

Thapa, S., Giri, S., & Ross, A. G. (2025). Extreme weather and climate-related adverse childhood experiences are a humanitarian crisis during the 21st century. Communications medicine, 5(1), 357. https://doi.org/10.1038/s43856-025-01089-x

Trost, K., Ertl, V., König, J., Rosner, R., & Comtesse, H. (2024). Climate change-related concerns in psychotherapy: therapists’ experiences and views on addressing this topic in therapy. BMC psychology, 12(1), 192. https://doi.org/10.1186/s40359-024-01677-x 

Tupinier Martin, F., Boudreault, J., Campagna, C., Lavigne, É., Gamache, P., Tandonnet, M., Généreux, M., Trottier, S., & Goupil-Sormany, I. (2024). The relationship between hot temperatures and hospital admissions for psychosis in adults diagnosed with schizophrenia: A case-crossover study in Quebec, Canada. Environmental research, 246, 118225. https://doi.org/10.1016/j.envres.2024.118225

Wang, X., Lavigne, E., Ouellette-kuntz, H., & Chen, B. E. (2014). Acute impacts of extreme temperature exposure on emergency room admissions related to mental and behavior disorders in Toronto, Canada. Journal of affective disorders, 155, 154–161. https://doi.org/10.1016/j.jad.2013.10.042

Woodland, L., Ratwatte, P., Phalkey, R., & Gillingham, E. L. (2023). Investigating the Health Impacts of Climate Change among People with Pre-Existing Mental Health Problems: A Scoping Review. International journal of environmental research and public health, 20(8), 5563. https://doi.org/10.3390/ijerph20085563

World Health Organization. (‎2022)‎. Mental health and climate change: policy brief. World Health Organization. https://iris.who.int/handle/10665/354104. License: CC BY-NC-SA 3.0 IGO

Published: November 18, 2025

Author: Jonathan Vicente dos Santos Ferreira, MSc
PhD Student at the Institute of Social and Preventive Medicine (ISPM), University of Bern

Editor: Colleen Rollins, PhD