People with mental illness are at increased risk of heat-related morbidity and death
Heat waves are associated with a 9.7% increase in mental health–related hospital presentations, and mental illness is one of the strongest predictors of heat-related deaths (odds ratio 3.61, 95% confidence interval 1.3–9.8).1,2 During the 2021 extreme heat event in western Canada (i.e., the heat dome), people with schizophrenia had the highest risk of death compared with people with other chronic conditions.3
Psychotropic medications increase heat vulnerability through several overlapping mechanisms
Although direct evidence on heat exchange mechanisms remains limited, medications can interfere with central thermoregulation (e.g., antidepressants, antipsychotics, stimulants), alter perception and compromise one’s ability to sense and respond to heat (e.g., antipsychotics, benzodiazepines), or induce dehydration-related drug toxicity (e.g., lithium).4
Even short exposures to extreme heat can cause clinically deleterious effects among people taking psychotropic medications
Prolonged exposure, which typically occurs among people without access to air conditioning, is particularly concerning for heat illness. Adverse effects already common to psychotropic medications, such as dry mouth and sweating, can also be exacerbated by extreme heat.
Polypharmacy, physical health comorbidities, and social vulnerability amplify the risks associated with heat
Other heat-sensitizing medications include antihypertensives, anticholinergics, and anti-Parkinson agents, which can cause reduced thirst sensation and hypotension.4,5 Concomitant chronic diseases that also elevate risk in extreme heat events include ischemic heart disease, pulmonary illness, and chronic kidney disease.1,3 Compounding sociodemographic risk factors include older age, pregnancy, poverty, homelessness, and substance use.
Physicians should provide clear, evidence-based guidance on heat protection as part of routine mental health care
Recommendations include hydrating pre-emptively, taking cool showers, minimizing exertion, and monitoring the temperature in one’s home to compensate for altered heat perception.6,7 Potential heat-related adverse effects should be balanced with the benefits of ongoing psychotropic treatment. Outreach, developing patient support networks, and promoting access to cooling are essential advocacy-oriented initiatives.
Footnotes
Competing interests: Siqi Xue reports grants from the University of Toronto Collaborative Centre for Climate, Health & Sustainable Care and SDGs@UofT (the sustainable development goals initiative at the University of Toronto), and travel support from the Japanese Society of Psychiatry and Neurology. No other competing interests were declared.
This article has been peer reviewed.
References
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