How Extreme Heat Can Worsen Mental Health

Man struggling with the heat.

Nataliia Nesterenko / Getty Images

Key Takeaways

  • A recent study found that extreme heat was linked to higher rates of mental health-related emergency room visits in the U.S.
  • Heat may exacerbate mental health symptoms in many ways.
  • Experts say we need to both prepare for climate change-related emergencies, which are already happening, as well as push for systemic changes that will decrease or slow down their harmful impacts.

We know a lot about the impacts of extreme heat on physical health. For example, on summer’s hottest days we are advised to be on the lookout for heatstroke warning signs.

But Amruta Nori-Sarma, PhD, MPH, professor of environmental health at Boston University, noticed that there wasn’t as deep an understanding about the relationship between extreme heat and mental health symptoms.

So, she and her colleagues compared the numbers of mental health-related emergency department visits in the U.S. during days of extreme heat and days with comparatively “optimal” temperatures. “We noted that there’s a trend of increasing emergency department visit rates associated with increasing temperatures,” Nori-Sarma told Verywell.

This is important to look at, experts say, because we’re likely to see more heatwaves as climate change worsens.

“Hotter average temperatures are one of the most tangible anticipated consequences of climate change, so it’s extremely important to see empirical evidence that shows it is already harming people’s mental health,” Francis Vergunst, PhD, a postdoctoral fellow in child development and psychopathology at the University of Montreal, who was not involved with the study, told Verywell via email.

The study was published in JAMA Psychiatry in late February.

Extreme Heat May Worsen Mental Health

Nori-Sarma and colleagues combed through insurance claims data for nearly 3.5 million emergency department visits in the U.S., between 2010 and 2019. They zeroed in on hotter-than-normal days, compared to relatively normal temperature days, in counties during the summer months.

After analyzing the data, they found that extreme heatwaves marked significant increases in mental health-related emergency room visits. Patients’ complaints ranged from symptoms of mood and anxiety disorders, substance use disorders, schizophrenia, and suicide risk.

“What [the data] indicates to us is that heat is an external factor that’s exacerbating existing problems in people with underlying mental health conditions,” Nori-Sarma said. “It’s so consistent across all of these different disorders that aren’t necessarily related.”

What Is It About Heat?

The researchers note that stress of any kind can exacerbate mental health problems; heat is just one kind. But because weather is becoming more extreme due to climate change, it’s worth looking into how heat specifically worsens mental health symptoms.

Exactly how heat affects people’s mental health isn’t known, Vergunst said, but there are several possible explanations. For example, the heat might increase overall stress by making the body more uncomfortable or disrupting sleep. Nori-Sarma added that extreme heat might also trigger anxieties about climate change.

The numbers found in the study are likely higher, too. Not everyone who experiences worsened mental health symptoms during extreme heat will go to the emergency room and have health insurance that allows them to seek care.

“Many more people, who were not admitted, could also be experiencing heat-related distress but receive no treatment or support,” Vergunst said. “The scale of this sub-clinical distress is unknown and also needs to be investigated.”

Impact of Climate Change on Health

We are already witnessing the devastating impacts of climate change on our communities. Wildfire smoke is increasingly affecting people’s lungs. Natural disasters like flooding have put people’s lives at risk.

Nori-Sarma spoke with traffic police in India who stand in the middle of intersections, eight hours a day. “They know that they cough more frequently,” she said. “They’re not necessarily able to identify the mechanisms by which air pollution is impacting their lung health, but they know that something is happening.”

Vergunst also studied how climate change can harm infants and children, starting from the moment of conception. “Early life is a period of extremely high developmental vulnerability,” he said.

And the stress that many young children go through when exposed to events like wildfires, floods, or strong storms—as well as their parents’ distress—can have lifelong effects on development. “When impacts are severe and occur early in development, they can trigger a cascade of maladaptive developmental changes that set children on developmental trajectories that ultimately undermine long-term health and wellbeing,” Vergunst said.

“These effects are already being observed and their frequency will increase as climate change advances,” he added.

What This Means For You

Climate change implicates everyone from the individual to big industry. While reducing, reusing, and recycling won’t do much alone, it can still be a helpful drop in the bucket—especially if it acts as a catalyst for learning more, reflecting on your own role in society, volunteering, and supporting communities and organizations working to impact policy and larger systemic change.

Individual and Collective Action As Therapy

Current news and research about climate change and health increasingly focus on climate change anxiety—also known as eco-anxiety. Diagnosing anxieties related to environmental issues can be helpful.

However, focusing on environmentally-related trauma and anxiety as a disorder to be treated with traditional talk therapy and drugs might be missing the mark. Shouldn’t efforts instead be put toward slowing the impact of climate change?

Vergunst said the two aren’t mutually exclusive. “I think the answer is that we need to do both—to urgently slow climate change and start developing ways to adapt and cope,” Vergunst said.

So, individuals, industry, and government need to be thinking short and long-term. Some of the short-term needs, Vergunst said, include:

  • Reducing greenhouse gas emissions by modifying individual behavior
  • Creating action within our communities
  • Voting, lobbying for representatives focused on holding industry accountable for reducing environmental emissions

“People need accurate information,” Vergunst said. “They need to understand that a livable planet for their children and grandchildren is hanging in the balance and that they are part of the solution. Otherwise, they won’t take on the responsibility required for action.”

But then again, how can people make changes to their daily lives if those changes aren’t convenient or even accessible? Evidence even suggests that placing emphasis on individual actions actually decreases willingness to make environmentally-conscious changes.

Here’s where the long-term thinking comes in. “It’s recognizing that climate change will be a part of our future and that we need to find ways to adapt and cope—as individuals, but also as a society, nationally and internationally,” Vergunst added.

We’ll never have everybody on board for climate justice and action, Vergunst added, but advocating for individual and collective action may be one way to combat eco-anxiety—not only for the self, but for the most vulnerable in society who are already directly impacted, and for future generations.

“I think it’s going to be tough,” he said. “The fact that we know what to do, though, is reason for optimism. We just need to do it.”

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Nori-Sarma A, Sun S, Sun Y, et al. Association between ambient heat and risk of emergency department visits for mental health among US adults, 2010 to 2019JAMA Psychiatry. Published online February 23, 2022. doi:10.1001/jamapsychiatry.2021.4369

  2. Vergunst F, Berry HL. Climate change and children’s mental health: a developmental perspective. Clin Psychol Sci. Published online September 14, 2021. doi:10.1177/21677026211040787

  3. Palm R, Bolsen T, Kingsland JT. “Don’t tell me what to do”: resistance to climate change messages suggesting behavior changes. Weather Clim Soc. 2020;12(4):827-835. doi:10.1175/WCAS-D-19-0141.1

By Sarah Simon
Sarah Simon is a bilingual multimedia journalist with a degree in psychology. She has previously written for publications including The Daily Beast and Rantt Media.