People with mental illness are at higher risk for poor physical and mental health due to extreme heat [High Confidence]. Increases in extreme heat will increase the risk of disease and death for people with mental illness, including elderly populations and those taking prescription medications that impair the body’s ability to regulate temperature [High Confidence].

This finding is from chapter 8 of The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment.

Process for developing key messages: The chapter was developed through technical discussions of relevant evidence and expert deliberation by the report authors at several workshops, teleconferences, and email exchanges. The authors considered inputs and comments submitted by the public, the National Academies of Sciences, and Federal agencies. For additional information on the overall report process, see Appendices 2–3.

Areas of focus for the Mental Health and Well-Being chapter were determined based on the most relevant available scientific literature relating to mental health, wellness, and climate change, as well as the mental health impacts of events associated with climate change. Much of the evidence on these impacts has been compiled in countries outside the United States; however, the scenarios are similar and the evidence directly relevant to the situation in the United States, and thus this literature has been considered in the chapter. The evidence-base on mental health and wellness following extreme weather disasters is both well-established and relevant to climate change. The existence of highly relevant scientific literature on specific concerns directly influenced by climate change—such as the effects of extreme heat, stress associated with the threat and perception of climate change, and special population risks—resulted in the inclusion of these more targeted topics. Although significant scientific literature for resilience exists, in-depth discussions of adaptation, coping, and treatment approaches are outside the scope of this chapter, but are discussed in brief in the Resilience and Recovery section.

Description of evidence base: Mental, behavioral, and cognitive disorders can be triggered or exacerbated by heat waves. An increased susceptibility to heat due to medication use for psychiatric and other mental health disorders, as well as for alcohol- and drug-dependent people, is supported by numerous studies,922bcd50-dd07-4e05-afc7-fe3bcb1a953a 898dabcf-7205-4007-8782-7f8fb4afa797 682bbf49-5c57-4e69-b031-d185d2480cf2 c142a857-65af-499e-9f99-3e1666903eca 7ed50d22-b382-4c8a-8794-7ec131587ebe 35822aeb-7ea0-4f88-8b90-6b8bd6c9c9cf 459504bb-a64e-4d70-8643-144ca33cb7fb and the influence of dehydration on the effects of psychotropic medications is well-documented.1e9a7907-02f2-4da8-9e93-131f92515dbc 898dabcf-7205-4007-8782-7f8fb4afa797 114cd0b9-5577-4c58-b5b1-24c822dd4ad7

A significant body of evidence shows that the combination of mental illness and extreme heat can result in increases in hospitalizations and even death.922bcd50-dd07-4e05-afc7-fe3bcb1a953a 1e9a7907-02f2-4da8-9e93-131f92515dbc 2a9775ae-a280-4260-985f-0e66d0ef8c11 987707c1-8e54-41d8-8555-c5e1d4bcc661 17cd07d1-5250-4980-8b98-689b4caf0bb1 Furthermore, six case-control studies, involving 1,065 heat wave-related deaths, have found that preexisting mental illness tripled the risk of death.e7927819-0782-42ff-a491-6e125f61600e In a more recent heat wave study, close to 52% of the heat-related fatalities were of people with at least one mental illness and half of those were taking a psychotropic medication.222f1cca-24a5-4d3f-b436-39ec256114ba

New information and remaining uncertainties: Uncertainties include whether pharmaceutical companies will develop new medications to treat mental illness and other health conditions that make individuals less susceptible to heat, whether strategies for prevention of heat-related illness and death are implemented, and whether individuals begin to adapt over time to increases in heat. Prevention, detection, and treatment of mental illness without the use of medications that negatively impact the body’s ability to regulate heat could moderate the magnitude of extreme heat’s impact on those predicted to have psychiatric and stress related disorders.

Assessment of confidence based on evidence: A large body of established scientific evidence shows there is high confidence that people with mental illness are at greater risk for poor physical and mental health outcomes from climate change. Similarly, there is high confidence that exposure to extreme heat will exacerbate such outcomes, particularly for the elderly and those who take certain prescription medications to treat their mental illnesses. Given predictions of growth in the subgroup of the population who have mental health conditions and who take pharmaceuticals that sensitize them to heat, increases in the number of people experiencing related negative health outcomes due to climate change is expected to occur.

References :

• Heat-related side-effects of neurological and non-neurological medication may increase heatwave fatalities (114cd0b9)
• Acute impacts of extreme temperature exposure on emergency room admissions related to mental and behavior disorders in Toronto, Canada (17cd07d1)
• Psychotropic drugs use and risk of heat-related hospitalisation (1e9a7907)
• Heat-related fatalities in Wisconsin during the summer of 2012 (222f1cca)
• Temperature-related deaths in people with psychosis, dementia and substance misuse (2a9775ae)
• Mortality in southern England during the 2003 heat wave by place of death (35822aeb)
• Morbidity and mortality during heatwaves in metropolitan Adelaide (459504bb)
• Recurrent heat-related illnesses during antipsychotic treatment (682bbf49)
• Heat wave: First, protect the vulnerable (7ed50d22)
• Heatwaves and their impact on people with alcohol, drug and mental health conditions: A discussion paper on clinical practice considerations (898dabcf)
• The Effect of Heat Waves on Mental Health in a Temperate Australian City (922bcd50)
• Relationship between ambient temperature and humidity and visits to mental health emergency departments in Québec (987707c1)
• The effete in the heat: Heat-related hospital presentations during a ten day heat wave (c142a857)
• Prognostic Factors in Heat Wave–Related Deaths: A Meta-analysis (e7927819)