Climate change: Why heatwaves kill more mentally ill people, what makes them so vulnerable?

A March research found that 8% of those who passed away in British Columbia's June 2021 heatwave — which broke all records—had a diagnosis of schizophrenia — compared to all other illnesses the authors evaluated, such as renal disease and coronary artery disease, this made the problem a more serious risk factor.

“Until climate change gets under control, things are only going to get worse unfortunately,” said Dr Robert Feder, a retired New Hampshire-based psychiatrist and the American Psychiatric Association’s representative to the Medical Society Consortium on Climate and Health. 

“As the temperature keeps increasing, these effects are going to be magnified. There’s going to be more storms, more fires, and people are going to be more worried about what could happen because a lot more things are happening.”

According to many researchers, rising temperatures have also been linked to an increase in emergency room visits due to mental health issues and suicide attempts. 

Furthermore, prolonged exposure to air pollution has been connected to higher levels of anxiety and a rise in suicides. The climate crisis has the potential to exacerbate this problem by adding additional particles from wildfires and droughts.

According to specialists, individuals with schizophrenia or other illnesses are more susceptible to excessive heat, air pollution, and stress due to a variety of factors in their brains. As such, they require help from loved ones, surrounding communities, and politicians.

The anterior hypothalamus, a region of the brain, is the starting point for what predisposes some mental health patients to the negative effects of excessive heat, including heatstroke and even death. Consider it the body's temperature regulator.

“That’s the part of the brain that is working to tell you — when you’re too hot or you’re too cold — to begin shivering, to begin sweating,” which, according to Dr Peter Crank, an assistant professor in the geography and environmental management department at the University of Waterloo in Canada, is the body's cooling system. 

A March research examining correlations between Phoenix, Arizona, temperatures and hospital admissions of individuals with schizophrenia was lead-authored by Crank.

“It tells the rest of your brain you need to take behavioral action, like drinking water or putting on a coat when it’s too cold or taking off a coat when it’s warm,” he added. 

“These disorders, whether it’s bipolar, schizophrenia or manic depressive — all three of them impair the neurotransmission of information to that portion of the brain.”

Experts speculated that brain chemicals like dopamine and serotonin, which are typically reduced in the brains of those with these diseases, may also have a role in the ability to control body temperature.

“The hypothalamus is directly dependent upon being stimulated by serotonin,” said Dr Joshua Wortzel, a psychiatrist at Bradley Hospital at Brown University in Rhode Island and chair of the American Psychiatric Association’s committee on climate change and mental health.

 “Serotonin levels in the brain are affected by temperatures outside, and so you can imagine that when we’re playing around with serotonin levels in the brain with our medicines, that can change a person’s ability to sweat.”

Certain drugs used to treat these conditions might increase the risk by increasing body temperature or impairing sweating.

According to Feder, antipsychotic drugs, which are frequently used to treat schizophrenia, bipolar disorder, paranoia, and delusions, had the biggest impact. These consist of lurasidone, risperidone, quetiapine, olanzapine, and aripiprazole.

This issue can also be brought on by some anti-anxiety drugs and stimulant treatments for attention deficit hyperactivity disorder, or ADHD, such as lisdexamfetamine and amphetamine/dextroamphetamine salts.

Feder also said that the mood-stabilising drug lithium might result in dehydration.

Lifestyle choices that are crucial for controlling mental health symptoms may also suffer. According to specialists, sleep is crucial for controlling mental health symptoms and might be disrupted by warm weather.

Additionally, “the nature of most mental health conditions is that once you’re diagnosed with it, you are at risk for recurrent episodes of that illness,” Feder said. “And these episodes are often brought on by some type of stress. And climate disasters are certainly a stress.”