Knowing Neurons
Mental HealthNeurological and Psychiatric Disorders

Schizophrenia and the Unseen Toll of Climate Change

By Elissavet Chartampila

June 29th, 2021, was the hottest day in history for British Columbia, Canada. As a heat wave swept across western Canada, temperatures soared to unprecedented heights, with some areas observing readings as high as 50oC (122oF). On this day alone, the scorching heat claimed the lives of 234 people (BC Coroners Service, 2022). As the heat wave persisted for a total of eight days, the death toll continued to climb, making it one of the deadliest weather events in Canadian history (Henderson et al., 2021). The extreme heat, which was promptly attributed to climate change (Philip et al., 2021), caused 576 deaths.

In a surprising finding, a recent study showed that the most vulnerable population during this extreme heat event was people with schizophrenia (Lee et al., 2023). In the study, epidemiologists in the Environmental Health Services at the British Columbia Center for Disease Control (BCDC) compared the prevalence of chronic diseases in individuals who died during the 2021 extreme heat event against that of individuals who died during the same period in previous years.

The usual suspects still emerged – diabetes, heart disease, pulmonary disease, and kidney disease. However, schizophrenia stood out as it incurred a three-fold increased risk of death, the highest among other chronic illnesses.

However, schizophrenia stood out as it incurred a three-fold increased risk of death, the highest among other chronic illnesses…

This study contributes to a growing body of research establishing a striking connection between extreme weather events and mental illness (Bundo et al., 2021; Hansen et al., 2008; Liu et al., 2021; Lohmus, 2018). However, this relationship is understudied, and the underlying physiological and environmental forces are poorly understood. Most likely, “it is the result of a complex set of interacting factors”, said Michael Lee, lead author and epidemiologist at the BCCDC, in an interview.

For example, mental illness is associated with stigmatization, social isolation, economic marginalization, and substance use, all of which, independently, are risk factors for heat-related mortality (Alegria et al., 2018; Henderson et al., 2022; Lohmus et al., 2018; Liu et al., 2021). The high prevalence of anosognosia among individuals with schizophrenia could also partially explain their increased vulnerability to heat (Liu et al., 2021). Anosognosia, the lack of awareness of one’s medical condition, could compromise the ability to appropriately respond to overheating or comply with public health guidelines. Compounding these risks, treatments for neuropsychiatric disorders, such as antidepressants and antipsychotics, can interfere with the activity of the hypothalamus, a brain region that controls the body’s ability to regulate its temperature, further increasing the risk of heat related illnesses (Lohmus, 2018). In follow-up studies, the BCCDC will attempt to elucidate which of these factors played a more significant role in driving mortality, says Dr. Lee.

… mental illness is associated with stigmatization, social isolation, economic marginalization, and substance use, all of which, independently, are risk factors for heat-related mortality…

The study by Lee and colleagues prompts us to reconsider which populations we previously considered vulnerable to climate change. According to Lee, “schizophrenia and severe mental health in general is not traditionally recognized as an important risk factor for dying during extreme heat.” However, with the frequency and intensity of extreme weather events expected to rise as a result of climate change (IPCC et al., 2021), it is imperative that public health policy and practices are appropriately adapted.

Mental illness has been added as a risk factor for heat-related illness in public health messaging in Canada and the United States (British Columbia Center for Disease Control, 2022; CDC, 2022). However, improving health outcomes during heat waves will also require drastic changes in infrastructure, health care systems and increased awareness at the population level (Patel et al., 2022).

… improving health outcomes during heat waves will also require drastic changes in infrastructure, health care systems and increased awareness at the population level…

Updating building codes to encourage the use of more effective cooling strategies for existing and new homes is an essential element of longer-term planning for British Columbia. Other priorities should include training health professionals to recognize and manage heat illness and equipping emergency systems with the necessary tools to handle the increased demand during extreme heat events (BC Coroners Service, 2022, Patel et al., 2022).

In a more bottom-up approach, BCCDC health officials, including Lee, are working closely with health authorities and organizations that serve vulnerable populations, such as the British Columbia Schizophrenia Society to spread awareness and facilitate outreach during extreme heat events. “Public policy is important, but preventing these deaths is everybody’s responsibility. It is up to all of us during these events to take action and prevent the deaths from occurring,” says Lee. It can be as simple as checking in on our neighbors, friends, and family who are at risk.

These community collaborations can then facilitate the development of more rigorous extreme heat response plans by allowing health systems to better understand the unique needs of the most vulnerable populations.

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Written by Elissavet Chartampila
Illustrated by Sneha Chaturvedi
Edited by Lauren Wagner and Sarah Wade

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References

Alegría, M., NeMoyer, A., Falgàs Bagué, I., Wang, Y., & Alvarez, K. (2018). Social Determinants of Mental Health: Where we are and where we need to go. Current Psychiatry Reports, 20(11). https://doi.org/10.1007/s11920-018-0969-9

British Columbia Center for Disease Control. (2022). BC provincial heat alert and response system (BC hars): 2022. http://www.bccdc.ca/resource-gallery/Documents/Guidelines%20and%20Forms/Guidelines%20and%20Manuals/Health-Environment/Provincial-Heat-Alerting-Response-System.pdf.

British Columbia Coroners Service. (2022). Extreme Heat and Human Mortality: A Review of Heat-Related Deaths in B.C. in Summer 2021. Government of British Columbia. https://www2.gov.bc.ca/assets/gov/birth-adoption-death-marriage-and-divorce/deaths/coroners-service/death-review-panel/extreme_heat_death_review_panel_report.pdf

Buckley, P. F., Wirshing, D. A., Bhushan, P., Pierre, J. M., Resnick, S. A., & Wirshing, W. C. (2007). Lack of insight in schizophrenia. CNS Drugs, 21(2), 129–141. https://doi.org/10.2165/00023210-200721020-00004

Bundo M, de Schrijver E, Federspiel A, Toreti A, Xoplaki E, Luterbacher J, et al. (2021) Ambient temperature and mental health hospitalizations in Bern, Switzerland: A 45-year time-series study. PLoS ONE 16(10): e0258302. https://doi.org/10.1371/journal.pone.0258302

Henderson, S. B., McLean, K. E., Lee, M., Kosatsky, T. (2021). Extreme heat events are public health emergencies. BC Medical Journal, 63(9), 366-367

Hansen, A., Bi, P., Nitschke, M., Ryan, P., Pisaniello, D., & Tucker, G. (2008). The effect of heat waves on mental health in a temperate Australian city. Environmental Health Perspectives, 116(10), 1369–1375. https://doi.org/10.1289/ehp.11339

Henderson, S. B., McLean, K. E., Lee, M. J., & Kosatsky, T. (2022). Analysis of community deaths during the catastrophic 2021 heat dome: Early evidence to inform the public health response during subsequent events in greater Vancouver, Canada. Environmental Epidemiology (Philadelphia, Pa.), 6(1), e189. https://doi.org/10.1097/EE9.0000000000000189

IPCC. (2021). Summary for Policymakers. In: Climate change 2021: The Physical Science Basis. https://www.ipcc.ch/report/ar6/wg1/chapter/summary-for-policymakers/

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), e2022GH000729. https://doi.org/10.1029/2022GH000729

Liu, J., Varghese, B. M., Hansen, A., Xiang, J., Zhang, Y., Dear, K., Gourley, M., Driscoll, T., Morgan, G., Capon, A., & Bi, P. (2021). Is there an association between hot weather and poor mental health outcomes? A systematic review and meta-analysis. Environment International, 153, 106533. https://doi.org/10.1016/j.envint.2021.106533

Lõhmus, M. (2018). Possible Biological Mechanisms Linking Mental Health and Heat-A Contemplative Review. International Journal of Environmental Research and Public Health, 15(7), 1515. https://doi.org/10.3390/ijerph15071515

Patel, L., Conlon, K. C., Sorensen, C., McEachin, S., Nadeau, K., Kakkad, K., & Kizer, K. W. (2022). Climate Change and Extreme Heat Events: How Health Systems Should Prepare. NEJM Catalyst, 3(7), CAT.21.0454. https://doi.org/10.1056/CAT.21.0454

Philip, S. Y., Kew, S. F., van Oldenborgh, G. J., Anslow, F. S., Seneviratne, S. I., Vautard, R., Coumou, D., Ebi, K. L., Arrighi, J., Singh, R., van Aalst, M., Pereira Marghidan, C., Wehner, M., Yang, W., Li, S., Schumacher, D. L., Hauser, M., Bonnet, R., Luu, L. N., … Otto, F. E. (2022). Rapid attribution analysis of the Extraordinary Heat Wave on the Pacific coast of the US and Canada in June 2021. Earth System Dynamics, 13(4), 1689–1713. https://doi.org/10.5194/esd-13-1689-2022

CDC. (2022). Protecting Vulnerable Groups from Extreme Heat https://www.cdc.gov/disasters/extremeheat/specificgroups.html

Author

  • Elissavet Chartampila

    Liza Chartampila is a second-year PhD student in the Neuroscience program at the University of North Carolina at Chapel Hill. Her current research focuses on understanding the role of sleep in development and neurodevelopmental disorders like autism and schizophrenia. Before beginning her doctoral studies at UNC, Liza completed her B.S. in neuroscience at Washington and Lee University and worked as a research assistant at New York University. Outside of research, she enjoys painting, hiking, reading, listening to podcasts, and playing sports (especially volleyball).

Elissavet Chartampila

Liza Chartampila is a second-year PhD student in the Neuroscience program at the University of North Carolina at Chapel Hill. Her current research focuses on understanding the role of sleep in development and neurodevelopmental disorders like autism and schizophrenia. Before beginning her doctoral studies at UNC, Liza completed her B.S. in neuroscience at Washington and Lee University and worked as a research assistant at New York University. Outside of research, she enjoys painting, hiking, reading, listening to podcasts, and playing sports (especially volleyball).