Summer’s soaring temps bring the well-known risks of heat exhaustion and heat stroke — but they can also take their toll on people’s moods and mental health, experts say.

Higher temperatures have been linked to an uptick in emergency room visits for mental health conditions and diagnoses, as found in a 2022 study published in JAMA Psychiatry.

The Boston University study looked at nearly 3.5 million adult ER visits between 2010 and 2019. 

“Our work showed that emergency department visits to treat mental health increased as ambient temperatures increased, for adults across the U.S. with commercial health insurance, for a wide range of illnesses,” lead study author Amruta Nori-Sarma, assistant professor of environmental health at Boston University, told Fox News Digital. 

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While the researchers didn’t dive into the specifics of how heat impacts the brain, Nori-Sarma identified heat as a stressor that exacerbates people’s underlying ill health. 

Dr. Joseph Galasso, CEO at Baker Street Behavioral Health in New Jersey, was not involved in the study but said its findings are in line with what he would expect.

“We do know that extreme heat has a significant impact on mood and behavior,” he told Fox News Digital. “In particular, we see increases in aggression and mood instability.”

He also said, “In terms of our behavior, we see both externalized aggression and hostility toward others, as well as internalized aggression, which can take the form of suicide attempts and self-harm.”

How extreme heat affects the brain

When people are uncomfortable, Galasso said, it typically changes their mood and behavior.

“Extreme heat can lower, across the population, our general ability to be resilient and to maintain our psychological defense system, because it is detecting an increase in stress,” he explained.

One hypothesis is that exposure to extreme heat may interfere with levels of serotonin, a neurotransmitter that is linked to mood and emotion regulation, though more research is needed to confirm this, Galasso said.

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“What we do know is that exposure to extreme heat affects our ‘emotional gatekeepers,’ or the systems that keep our psychological resources and defenses intact,” he explained. 

One major factor could be that rising temperatures tend to disrupt sleep, the doctor said, which leads people to feel irritable and agitated.

“Further, people report greater difficulty with memory, attention, concentration and reaction time,” Galasso said. “When there is pressure on the internal systems that regulate mood and frustration, symptoms occur that make us feel less effective in our daily lives.”

“Exposure to extreme heat affects our ‘emotional gatekeepers,’ or the systems that keep our psychological resources and defenses intact.”

“For those with preexisting mental health conditions, this can often be the precursor to an increase in pathology,” he added.

Those who have mood instability, a history of substance abuse, or a severe or persistent mental illness are most vulnerable, Galasso warned — along with people in lower socioeconomic classes who may not have access to air conditioning and/or temperature-controlled environments.

Summer’s soaring temperatures can take a toll on people’s moods and mental health, studies have shown. (iStock)

Additional studies have found that periods of extreme heat also tend to trigger a surge in violent activity.

A 2021 study published in The Lancet found a link between rising temperatures and violent crimes, including homicides, sex offenses and assaults.

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One theory is that “hot weather induces interpersonal violence by increasing discomfort, frustration, impulsivity and aggression,” wrote the researchers from the School of Public Health and Preventive Medicine at Monash University in Melbourne.

A second theory was that temperature increases led to changes in people’s routine activities, which then sparked interpersonal conflicts.

How to keep a cool head in the heat

To prevent heat-induced meltdowns, Galasso emphasized the need for the public — particularly those who are most vulnerable — to have access to cooling centers, water and medical care.

“As mental health providers, we need to provide education to our clients and communities to help mitigate some of the negative effects of extreme heat,” he said. 

Higher temperatures have been linked to an uptick in emergency room visits for mental health conditions and diagnoses. (REUTERS/Mike Blake)

“And it is important for first responders to understand that they may see an increase in violence, domestic violence, aggression and heat-related issues,” Galasso added.

People who are taking psychotropic medications also need to know that some types of drugs impair the body’s ability to regulate temperature, he said.

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Many cities across the U.S. have emergency preparedness programs to help vulnerable people cope with the heat, pointed out study author Nori-Sarma. 

The National Center for Healthy Housing’s website lists cooling centers by state.

“One of the best ways we have to cope with heat waves is to rely on our social networks — friends checking in on friends and loved ones, neighbors keeping an eye on neighbors — to make sure that everyone who may be impacted by extreme heat is cared for,” Nori-Sarma added.