Climate change and mental illness: What psychiatrists can do

“ Hope is engagement with the act of mapping our destinies.” ¹

—Valerie Braithwaite

Why should psychiatrists care about climate change and try to mitigate its effects? First, we are tasked by society with managing the psychological and neuropsychiatric sequelae from disasters, which include climate change. The American Psychiatric Association’s position statement on climate change includes it as a legitimate focus for our specialty.² Second, as physicians, we are morally obligated to do no harm. Since the health care sector contributes significantly to climate change (8.5% of national carbon emissions stem from health care) and causes demonstrable health impacts,³ managing these impacts and decarbonizing the health care industry is morally imperative.⁴ And third, psychiatric clinicians have transferrable skills that can address fears of climate change, challenge climate change denialism,⁵ motivate people to adopt more pro-environmental behaviors, and help communities not only endure the emotional impact of climate change but become more psychologically resilient.⁶

Most psychiatrists, however, did not receive formal training on climate change and the related field of disaster preparedness. For example, Harvard Medical School did not include a course on climate change in their medical student curriculum until 2023.⁷ In this article, we provide a basic framework of climate change and its impact on mental health, with particular focus on patients with serious mental illness (SMI). We offer concrete steps clinicians can take to prevent or mitigate harm from climate change for their patients, prepare for disasters at the level of individual patient encounters, and strengthen their clinics and communities. We also encourage clinicians to take active leadership roles in their professional organizations to be part of climate solutions, building on the trust patients continue to have in their physicians.⁸ Even if clinicians do not view climate change concerns under their conceived clinical care mandate, having a working knowledge about it is important because patients, paraprofessional staff, or medical trainees are likely to bring it up.⁹

Climate change and mental health

Climate change is harmful to human health, including mental health.¹⁰ It can impact mental health directly via its impact on brain function and neuropsychiatric sequelae, and indirectly via climate-related disasters leading to acute or chronic stress, losses, and displacement with psychiatric and psychological sequelae (Table 1^11-29).

Direct impact

The effects of air pollution, heat, infections, and starvation are examples of how climate change directly impacts mental health. Air pollution and brain health are a concern for psychiatry, given the well-described effects of air deterioration on the developing brain.¹¹ In animal models, airborne pollutants lead to widespread neuroinflam­mation and cell loss via a multitude of mechanisms.¹² This is consistent with worse cognitive and behavioral functions across a wide range of cognitive domains seen in children exposed to pollution compared to those who grew up in environments with healthy air.¹³ Even low-level exposure to air pollution increases the risk for later onset of depression, suicide, and anxiety.¹⁴ Hippocampal atrophy observed in patients with first-episode psychosis may also be partially attributable to air pollution.¹⁵ An association between heat and suicide (and to a lesser extent, aggression) has also been reported.¹⁶

Worse physical health (eg, strokes) due to excessive heat can further compound mental health via elevated rates of depression. Data from the United States and Mexico show that for each degree Celsius increase in ambient temperature, suicide rates may increase by approximately 1%.¹⁷ A meta-analysis by Frangione et al¹⁸ similarly concluded that each degree Celsius increase results in an overall risk ratio of 1.016 (95% CI, 1.012 to 1.019) for deaths by suicide and suicide attempts. Additionally, global warming is shifting the endemic areas for many infectious agents, particularly vector-borne diseases,¹⁹ to regions in which they had hitherto been unknown, increasing the risk for future outbreaks and even pandemics.²⁰ These infectious illnesses often carry neuropsychiatric morbidity, with seizures, encephalopathy with incomplete recovery, and psychiatric syndromes occurring in many cases. Crop failure can lead to starvation during pregnancy and childhood, which has wide-ranging consequences for brain development and later physical and psychological health in adults.^21,22 Mothers affected by starvation also experience negative impacts on childbearing and childrearing.²³

Indirect impact

Climate change’s indirect impact on mental health can stem from the stress of living through a disaster such as an extreme weather event; from losses, including the death of friends and family members; and from becoming temporarily displaced.²⁴ Some climate change–driven disasters can be viewed as slow-moving, such as drought and the rising of sea levels, where displacement becomes permanent. Managing mass migration from internally or externally displaced people who must abandon their communities because of climate change will have significant repercussions for all societies.²⁵ The term “climate refugee” is not (yet) included in the United Nations’ official definition of refugees; it defines refugees as individuals who have fled their countries because of war, violence, or persecution.²⁶ These and other bureaucratic issues can come up when clinicians are trying to help migrants with immigration-related paperwork.

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