RESEARCH WEEKLY: Extreme heat and severe mental illness
By Elizabeth Sinclair Hancq
(November 8, 2023) The summer of 2023 was considered the summer of extreme heat in America, with temperatures reaching the triple digits in many states across the United States. In early August, more than one-third of Americans experienced average temperatures in the 90s or above for three straight weeks. These extreme temperatures have many negative health effects, including immediate risks, such as dehydration or heat stroke, but also long-term impacts, such as heart attacks or diabetes complications.
People with severe mental illness (SMI) are at heightened risk for mortality during extreme heat events. As I wrote in March, people with schizophrenia were four times more likely to die during British Columbia’s heat dome event in 2021.
A recent Washington Post report chronicled the experience of people with SMI during extreme heat conditions in Phoenix, Arizona. When chronicling the last few days before the death of a man named Stephen, the authors wrote:
And one factor stands out as potentially the most dangerous preexisting condition in a rapidly warming world — not just because it makes people struggle to find safety in moments of extreme heat, but also because it makes their bodies physically more vulnerable to the heat. It’s the condition that Stephan was diagnosed with in his late 20s: schizophrenia.
Research published in 2022 suggests that extreme heat in Pheonix is causing an increase in hospitalizations for people with schizophrenia. The researchers estimate that healthcare costs attributed to schizophrenia hospitalizations due to non-optimal temperatures is $1.95 million annually in the city.
People with schizophrenia have difficulty with temperature regulation; a research study conducted in the 1930s found that people with schizophrenia placed in a hot room had body temperatures that rose faster and higher than those without schizophrenia. Some researchers believe it has to do with the impact of schizophrenia on the hypothalamus, which is the brain region involved in temperature regulation. Others think it is due to altered dopamine levels resulting in the inability for the body to cool itself off.
There are four additional factors that make someone with schizophrenia more at risk for heat-related death:
- Symptoms of schizophrenia: lack of insight or disorganized thinking can result in someone being unable to recognize one’s risk during extreme heat events or take proper precautions.
- Social isolation: people with schizophrenia are often socially isolated from others, which is a risk factor for heat-related illness and mortality, because there is no one monitoring their well-being.
- Co-occurring conditions: people with severe mental illness often have co-occurring conditions that increased one’s risk for heat-related deaths, such as heart disease or diabetes.
- Psychotropic medications: some medications used to treat schizophrenia have anticholinergic properties that can affect thermoregulation and result in increased susceptibility to heat. Additionally, lithium, commonly used to treat bipolar disorder, can be toxic if the user is dehydrated.
As extreme heat conditions are only expected to get worse with rising global temperatures, experts suggest that city and local officials in Phoenix and elsewhere must include people with severe mental illness as a vulnerable population to prioritize the protection of during these weather events. As the authors of the Washington Post article wrote, “under psychosis, a patient might walk for miles engaging only with the voices and characters in their own mind. Under normal conditions, that might simply be dangerous. In Phoenix, it’s deadly.”
References
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Chen, S. X., et al. (2023, June). Risk of mortality among people with schizophrenia during the 2021 heat dome. BC Medical Journal.
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Cornwall, W. (2023, March 15). Schizophrenia pinpointed as a key factor in heat deaths. Science.
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Crank, P. J., et al. (2022, October). Mental health and air temperature: Attributable risk analysis for schizophrenia hospital admissions in arid urban climates. Social Science Research Network.
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Osaka, S., et al. (2023, September 6). Heat’s hidden risk. Washington Post.
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