Climate Change and Heat-Related Illness: Opportunities for Prevention in Psychiatric Practice

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“For now, these hot days, is the mad blood stirring.”

-William Shakespeare

Headlines reel after a major heat wave: stories link the rise in temperature to climate change. A psychiatrist learns that 1 of her patients has been hospitalized in the medical following intensive care unit (ICU) for hyperthermia. The patient is being treated for heat stroke and is also floridly psychotic. The psychiatrist, sitting at her desk, thinks about the headlines and its impact on her patient and practice.

The challenges posed by climate change, including heat exposure, have become increasingly relevant in today's health practice, including psychiatry. This article highlights concerns posed by extreme heat events, and explores preventive psychiatry and community proactive care, including primary, secondary, and tertiary measures. It also investigates the increasing importance of viewing mental health under the climate lens in the context of the biopsychosocial-ecological model: highlighting avenues for enhancing community awareness and advocacy.

Climate Change and Heat Exposure

Climate change has been declared as the greatest threat to human health in the 21st century.¹ It has been accelerated by human activities, the most important of which is the burning of fossil fuels.² A major effect is disproportionally higher temperatures in cities, known as the urban heat island, further exacerbating heat stress.³ These developments have major significance, as excess heat is the deadliest weather-related hazard in the United States.⁴

Heat Exposure and Mental Health

Nigel Bark, MD, notes that patients with psychiatric disorders are at increased risk due to a physiological vulnerability, as the neurotransmitters that are involved in thermoregulation are also involved in the disease processes of schizophrenia and depression.⁵ Neuroleptics, in particular, have varying degrees of anticholinergic and anti-alpha-adrenergic effects. Both impair heat dissipation; anticholinergic properties decrease sweating and alpha-adrenergic blockade causes vasodilation, which may enhance heat absorption from the environment.⁶ The pharmacokinetics of some drugs such as lithium or antiepileptic drugs could also be altered by dehydration.⁷

Exposure to excess heat can result in the spectrum of heat-related illness ranging from mild heat cramps and heat rash, to more serious heat exhaustion and life-threatening heat stroke. Accordingly, the incidence, hospital admission rate, and risk of mortality for many mental health disorders have been associated with increased ambient temperature.⁷ Patients with schizophrenia, for example, have been demonstrated to be more vulnerable to heat and therefore have a higher chance of needing health care services in hotter environments.⁸

Researchers found that psychiatric hospitalization risk increased linearly by 4% every 10°C increase in mean daily temperature.⁹ Mortality rates of psychiatric populations have been noted to increase with warmer temperatures. In extreme heat, the use of alcohol, medications, and illegal drugs is further associated with an increased risk of mortality.¹⁰

The Role of Preventive Psychiatry

Primary, secondary, and tertiary prevention are important facets of preventive psychiatry and in preventing and managing heat-related illness in mental health populations.

Examples of primary prevention in attenuating modifiable risk factors relating to heat exposure include counseling patients on restricting physical activity to the coolest period of the day, seeking out air-conditioned buildings, drinking fluids frequently without waiting for the feeling of thirst, and wearing breathable, light-colored clothing and wide-brimmed hats. Recommendations for primary prevention include proper hydration and nutrition. This can include the integration of fruits and vegetables into one’s diet.¹¹ Other early prevention measures include flagging the charts of patients in high-risk groups and developing mechanisms to check on vulnerable patients during heat waves. Knowledge of community heat response or heat alert plans can enhance safety.¹² Mental health professionals, for example, can participate in disaster response training, including heat waves. Advocating for vulnerable groups such as the elderly and disabled in our ever-changing environment would also enhance primary prevention measures.

As heat exposure can exacerbate psychiatric disorders, facilitating access to treatment is paramount in secondary prevention. Therapy, including cognitive behavior therapy (CBT), can play a vital role in coping with heat‐induced mental stress, especially in individuals with depression and anxiety. Stress management strategies include maintaining a regular sleep schedule, eating a balanced diet, and staying hydrated.¹¹ Screening for early symptoms of mental illness related to heat disorders is an important facet of secondary prevention. Adjusting patients’ medications is crucial, when considering protecting heal-vulnerable individuals.

In psychiatry, tertiary prevention of climate change-related heat illness involves preventing relapse, reducing the likelihood of developing comorbidities, and providing treatments to enhance psychosocial functioning. Tertiary prevention goals include the prevention of nonadherence to medication.¹³ A collaborative care approach aims to improve patient education and integrate mental health professionals into the primary care arena as consultants and partners.14 This would include fostering regular follow-up appointments and utilizing family support.

The Table displays the array of measures mental health personnel can take in addressing climate change related heat illnesses.

Table. Preventive Strategies in Climate Change Related Heat Disorders

Preventive Psychiatry and the Biopsychosocial-Ecological Model

The biopsychosocial-ecological model builds on Engel’s biopsychosocial model and can be an integral framework when addressing heat-related illness in mental health practice linked to climate change. It adds the physical environment as a fourth interacting element to the dynamic interactions of the body, mind, and sociocultural variables presented by the biopsychosocial model.¹⁵ Salas et al have proposed viewing health care under a climate lens, assessing climate change-driven health risks and integrating them into policies and other actions to improve the nation’s health.¹⁶ This lens can be applied to preventive mental health measures in preventing heat exposure illnesses, where broad preventive measures integrate community-driven policies and programs with clinical care (Figure).

Figure. Aggregate Model for Preventive Psychiatry Along the Biopsychosocial-Ecological Continuum

This continuum, when viewed through a climate lens, helps place preventive measures for climate change-related health issues, specifically heat stress, under focus and helps visualize the comprehensive way biopsychosocial and environmental measures can be employed.

Clinical Vignette

“Kyle,” a 23-year-old homeless man, in a large urban area, with a history of schizoaffective disorder, had been increasingly paranoid, labile, and isolative. He remained partially compliant with medications including Risperdal and lithium. He was found on the side of a street with ambient temperatures reaching 106° F. The patient was confused, tremulous, lethargic, and disoriented; his pulse was progressively weak and he subsequently became combative. After arriving at the ICU, Kyle was found to be severely dehydrated with a core temperature of 103°F. He was treated for heat stroke complicated by lithium toxicity. He was subsequently rehydrated, and after hospitalization was placed back on medications, and Trileptal replaced lithium. Family support was enlisted, he was linked to his primary care provider, and he returned to a stable environment. Kyle and his family were educated on proper hydration.

In this case vignette, we can see the interface between Kyle’s biopsychosocial vulnerabilities and the environmental impact of climate change stemming from a heat wave in an urban environment. Primary preventive strategies would have included education and adequate shelter in a cool environment. It would have also included flagging Kyle’s chart as hot weather approached and provided education on optimal hydration and nutrition. Secondary prevention entails mitigation of illness stemming from his heat stroke and lithium toxicity. Adjusting the Kyle’s medications include considering alternatives to lithium when planning secondary preventive measures in heat vulnerable individuals. Moving forward, tertiary preventive strategies would include buttressing social and family support and collaborating with his primary care providers to ensure follow-up and medication compliance.

Discussion: Expanding the Arm of Preventive Psychiatry in Climate Change

As climate change is transforming our physical environment, psychiatrists are in a unique position to intervene along the entire spectrum of prevention of heat-related morbidity and mortality, at both the individual and population levels. Because heat-related illness and mortality are preventable by taking protective action, successfully communicating heat risk to the public can be a highly effective way to save lives and reduce economic impacts.⁴

For today’s psychiatrist, a critical question is “What does climate change mean for me, my patients, and my clinical practice?” Psychiatrists have a primary responsibility to their patients, the community, and beyond. A collaborative approach is important in addressing the global dimensions of climate change. Ultimately, psychiatrists can play an important leadership role in the prevention of illness related to climate change.

Lise Van Susteren, MD, points out that “mental health professionals are well-positioned to challenge denial, influence public policy, and care for the victims of climate disasters because of their clinical training and expertise. They can address psychological mechanisms of defense and harmful behavior and use their skills to treat the impacts of illness and injury.”¹⁷ This viewpoint accentuates the need for mental health clinicians to not only be aware of the impact of climate change and incorporate it into practice but also to educate others and engage in public policy decisions that mitigate its impact.

Psychiatrists are in a unique position to directly embody physician humanitarianism because they can see first-hand how climate change is negatively affecting vulnerable populations. Psychiatrists should advocate for and protect their patients by providing proactive care as well as thoroughly educating communities about the health risks associated with extreme heat. Leading public policy initiatives and participating in advocacy organizations are excellent steps to take to spread awareness and are essential in supporting the well-being of their patients through this moral and ethical imperative. Humanitarianism, magnified from the lens of a physician’s perspective, is more important to practice now than ever, as their primary experience in treating patients whose conditions are worsened by the effects of climate change gives them a reputable and respected voice in the field. This allows psychiatrists to fulfill their duty to promote equity in health care and join communities together in the challenges that climate change brings. In our ever-changing climate, practicing preventative psychiatry is more important than ever, to ensure patient safety and stability.

Dr Stea is a psychiatrist in Hopkinsville, Kentucky and is affiliated with Western State Hospital-Hopkinsville. Mr Iqbal is a senior student at the University of Kentucky, where he is majoring in neuroscience.

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