Researchers say extreme heat is making mental health crises more common

‘I’ve never been this hot before’: Canadian in UK A Canadian living in London, U.K., says the heat wave is a cultural shock, with most of the country unprepared for high temperatures.

Health-care researchers are warning about the effects of high temperatures on mental health, amid a string of heat waves in Europe, the United Kingdom and North America.

The World Economic Forum published a report on high temperatures and mental health on July 14, citing more than 10 studies from countries around the world. The report highlighted how extreme heat and humidity are linked to heightened symptoms in people with depression, generalized anxiety disorder and bipolar disorder, according to a 2020 study out of the United Kingdom.

The report cited other research out of the U.K. that also linked extreme heat and humidity with higher suicide rates, as well as a study out of Australia that found that for every one degree increase in monthly average temperature, mental health-related deaths increase by 2.2 per cent.

Heat and humidity have also even been linked to a rise in manic episodes in people with bipolar disorder, the World Economic Forum reports, citing a 2021 study published in the European Journal of Psychiatry.

In Canada, mental health workers have personally seen how heat waves and climate change affect people, particularly among more vulnerable populations.

Stacy Ashton is executive director of the B.C. Crisis Centre. She worked during last year’s heat wave that killed more than 600 people in British Columbia between June 25 and July 1. Ashton remembers it was a busy time for her organization, which operates helplines for people experiencing mental distress and suicidal thoughts.

"We saw more calls coming in…and some of the health authorities had phone calls they wanted us to make to isolated folks that they were concerned about,” Ashton said. “It was very busy.”

Ashton said the B.C. Crisis Centre sees an increase in calls whenever a heat wave settles in, explaining that people with anxiety disorders can spiral once triggered by extreme weather events.

"We are definitely seeing more calls around anxiety related to climate change and that's because things like generalized anxiety disorder and other anxiety conditions will connect to anything that seems like a reason to be anxious, and then it gets into a vicious cycle,” Ashton said.

THE CONNECTION TO HEAT

The mechanisms by which heat worsens stress and anxiety are complex, but one study by researchers in Poland in 2018 concluded hotter temperatures increase the level of the stress hormone cortisol in our blood, while another study published in the United States National Library of Medicine in 2006 found our bodies produce more adrenaline when subject to heat stress.

"There's consistent evidence from around the world that shows weather extremes are linked to a whole gamut of increased mental health challenges,” Sean Kidd, clinical psychologist at the Centres for Addiction and Mental Health (CAMH) told CTVNews.ca on Tuesday.

"Another thing worth mentioning is the impact of heat on people's cognitive functioning, as well as emotional distress and dysregulation. People can become fatigued. People can have difficulty thinking clearly.”

Kidd is a senior scientist and chief of psychology at CAMH, whose primary research focuses on the effects of climate change on impoverished populations. He said isolated seniors, people experiencing poverty who may not have access to air conditioning and pregnant women whose body temperatures are already elevated are especially susceptible to the effects of extreme heat.

Katie Hayes, senior policy analyst with Health Canada, added that high temperatures also put people who take mood stabilizing medications at risk.

“For people who've been diagnosed with some mental illnesses, the medications they take — like some psychotropic medications — can affect people's ability to regulate their body temperatures,” Hayes said in an interview with CTV News.ca on Tuesday. “The medications people are on to treat mental illness can also be affected by the heat."

Hayes studies the mental health effects of climate change through her role in the Climate Change and Innovation Bureau of the Safe Environment Directorate at Health Canada.

She co-authored Health Canada’s 2022 report, “Health of Canadians in a Changing Climate,” which looked at the array of negative health effects Canadians are facing due to climate change, as well as ways individuals and governments can mitigate those effects.

Hayes said that while there’s no universal solution, individuals can reduce the effects of heat-induced dread and anxiety by seeking out mental health supports, connecting with their neighbours and communities and engaging in climate activism, if they’re able to.

Governments should develop comprehensive climate change adaptation plans that include strategies for protecting the most vulnerable populations, Hayes said. She pointed to Canada’s forthcoming National Adaptation Strategy as an example.

“The federal government is currently working on the first ever National Adaptation Strategy that has a health and wellbeing component that will include strategies looking at climate change and mental health."

Once completed later in 2022, the strategy will outline how Canada can become more resilient and prepare for the impacts of climate change across multiple sectors and systems.

If you or someone you know is struggling with suicidal thoughts or mental health matters, please call the National Suicide Prevention Lifeline at 800-273-8255 (or 988 beginning July 16, 2022) or Canada's Talk Suicide 1-833-456-4566. The following resources are also available to support people in crisis: