Heat Resilience and Severe & Persistent Mental Illness

In the 2021 heat dome event that affected British Columbia, 309 people living with schizophrenia died. The odds ratio for schizophrenia among all heat event deaths was 3.07. ¹

The World Health Organization has called climate change the greatest health threat of this century, and it is already affecting the health of people in Canada. Climate change affects physical health through heat-related illness; flood and wildfire-related deaths and displacement; wildfire-related lung and heart disease; increased tick-borne disease; longer allergy seasons; and increased food insecurity. Climate change also results in multiple repercussions for mental health, including increased incidence of post-traumatic stress disorder; worsening symptoms of pre-existing mental illness; and increased risk of aggression and suicide. ² The Canadian Psychiatric Association recently issued an urgent appeal for greater involvement of the Canadian psychiatric community in combating and adapting to the climate crisis. ³

People who are already structurally marginalized face the greatest health risk from climate change; just like the COVID-19 pandemic, climate change is a threat multiplier, worsening existing inequities. People who experience multiple structural and historic inequities face particularly amplified risk.

As a consequence of the warming climate, extreme heat is increasing globally and across Canada, with many regions projected to see a 3-fold to 4-fold increase in days above 30 degrees Celsius. Extreme heat is the greatest climate-related threat for those living in Canada; in fact, the 2021 heat dome event was the deadliest weather event in Canadian history. Government of Canada. ⁴

Groups whose health is most at risk from the heat include those with increased exposure to extreme heat, those with increased sensitivity to the heat, and those with limited access to appropriate resources or information. ⁵ People with Severe and Persistent Mental Illness (SPMI) fall into each of these risk categories.

Many factors contribute to increased heat-related illness and death in people living with SPMI: positive and negative symptoms may lead to social isolation, withdrawal, or neglect of personal hygiene; positive and cognitive symptoms may impair comprehension of important risk information or the ability to problem-solve. ⁶ In addition, people with SPMI may wear redundant clothing, contributing to overheating. People with SPMI may experience poor insight into their health status, including poor insight into emerging symptoms of heat-related illness. Comorbid substance use, especially stimulant use, can lead to hyperthermia; and comorbid malnourishment increases the risk of heat-related illness. Neuroleptic medications can raise body temperature and impair thermoregulation, and direct hypothalamic neurobiological changes can impair thermoregulation. ⁷

People with SPMI are more likely to experience homelessness, with direct exposure to outdoor heat and exposure to indoor heat in congregate settings such as shelters and boarding homes; more likely to live in densely populated, poor neighbourhoods subject to the urban heat island effect; and more likely to experience poverty with consequent difficulty accessing air conditioning.

People with SPMI are also more likely to suffer chronic physical conditions such as asthma, coronary artery disease, and diabetes, which are risk factors for heat-related illness.

Psychiatrists and all service providers who care for people with SPMI must take action to increase resilience to extreme heat among their patients. Service providers can act at the patient, or micro level; the community, or meso level; and the policy, or macro level.

Although the medications used to treat schizophrenia can affect thermoregulation, there is no evidence to support interruption of medication use during extreme heat events. Medication use is only one of many risk factors for people with SPMI. Stopping medications is unlikely to significantly reduce heat-related risks, and is likely instead to lead to other complications. Protective interventions should focus on addressing other risk factors. ⁶

At the micro level, providers should educate patients about staying cool during extreme heat events. For example, patients should be advised to use a fan or air conditioner (or a more energy-efficient heat pump) if they have one; keep shades and curtains closed during the day; drink water before feeling thirsty; minimize caffeine and alcohol intake; avoid using the oven; take cool baths and showers; wear light-coloured, loose-fitting clothing. ⁵ PreparedBC has a plain language Extreme Heat Guide that can be printed and given to patients.

Drawing from Cognitive Adaptation Training principles ⁸ environmental cues may be helpful for patients with prominent negative or cognitive symptoms (e.g., easy-to-read posters displayed prominently in clinic or housing settings, clothing that is appropriate for the weather laid out and organized for the whole week). Finally, providers can advocate for funding for air conditioners from disability support. For example, patients enrolled in the Ontario Disability Support Program are eligible for funding for an air conditioner for health reasons. Some patients who receive Ontario Works, the province's non-disability social welfare program, are also eligible.

At the meso level, community mental health teams should actively maintain a list of at-risk patients and check in on them during extreme heat. To facilitate this process, dedicated time could be set aside during daily team rounds (e.g., for Assertive Community Treatment and Intensive Case Management teams). Organizations should provide training to frontline clinicians on how to conduct a “heat check”; the National Collaborating Centre for Environmental Health has developed a helpful guide to conducting such assessments. Clinicians should review local public cool spaces such as libraries, churches, or municipal cooling centres, and lists of respite spaces and other publicly available resources should be provided to patients or posted in clinical spaces. For example, the City of Toronto's webpage on Staying Safe in Hot Weather lists cooling centres in Toronto.

That said, cooling centres are often less effective for the most vulnerable, who face barriers to accessing them, including stigma, the need to travel far from home, and a tendency not to view themselves as “vulnerable.” Psychiatrists and community mental health workers can collaborate with local public health officials and community support agencies to help make respite spaces accessible, inclusive, and desirable to spend time at for people with SPMI (e.g., by offering activities or social programmes, which may also have dual benefits for mental health). Mental health clinicians can also help public health officials effectively communicate the risks of extreme heat to and for people with schizophrenia.

At the macro level, psychiatrists and other mental health providers can engage in advocacy efforts to create policies that will protect vulnerable patients—for example, supporting community organizations in advocating for maximum temperature bylaws. In particular, health-care providers are well-positioned to advocate for systemic interventions that have immediate health co-benefits. ⁹ Tree planting in urban heat islands can, for example, decrease peak neighbourhood temperatures while also increasing access to green space, which is good for both physical and mental health.

And at the highest level, mental health clinicians should advocate for systems-level action on the climate crisis. The burning of fossil fuels should be named as an upstream determinant of ill health (and ill mental health), and all health workers should join calls for the rapid decarbonization of the economy.

People living with SPMI are at significantly increased risk of heat-related illness. As the climate crisis worsens over the coming years and decades and extreme heat events increase in duration, frequency, and intensity, psychiatrists and other mental health workers must act to protect people living with SPMI from heat-related harm.