Yes, Heat Takes a Toll on Mental Health—Here’s the Data

Data highlighting how heat affects mental health—plus tips on how to access compassionate, evidence-based care.

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The climate crisis is often framed as an environmental and economic emergency, but our warming planet is also a growing mental health crisis. As global temperatures rise, studies show a clear link between extreme heat and worsening psychological well-being. From increased hospitalizations to higher suicide rates, the data is clear: high temperatures can fuel distress.

The influence of temperature on daily life and its effects on mental health are often underestimated or overlooked. Recognizing this gap, experts have recently focused on investigating how high temperatures affect mental health. Chronic heat stress, for example, can cause elevated stress levels, anxiety, and even impair cognitive functioning, a 2023 report found. 

The effects of heat-related mental health distress aren’t felt equally across all groups. Research consistently shows that young children, older adults, and those with pre-existing mental health conditions are more at risk, with socioeconomic factors further increasing risk. Among these groups, young people (who are slated to endure the longest-lasting impacts of the climate crisis) have been among the most studied. A 2023 report found that the effects of climate change, including exposure to heat, increase the risk of anxiety, depression, PTSD, and other mental health challenges for young people. 

To better understand how heat affects mental health, Charlie Health reviewed findings from recent research around the world. Below, we outline key insights into this pressing public health crisis, as well as tips for finding support for your mental health. Remember: if climate stressors (or other life stressors) are taking a toll on your well-being, you’re not alone. Charlie Health offers compassionate, virtual treatment programs. Fill out our quick form to start healing today.

1. Heat and humidity can worsen mental health symptoms

When people live in places with higher temperatures, it can increase the risk of developing mental health symptoms or conditions. For instance, a 2019 study from Taiwan found that long-term exposure to temperatures above 73.4°F increases the risk of developing major depression by 7% for each 1°C rise. Similarly, research from Australia found that a 1°C rise in temperature and a one hPa increase in humidity (the metric for measuring humidity) were each linked to small increases in high psychological distress, including worsening anxiety and depression symptoms. And, when humidity was very high (99th percentile), the impact of heat on psychological distress more than doubled to 0.5%, researchers found.

2. Hospital visits for mental health conditions spike during heatwaves

Research from multiple countries shows that psychiatric hospital admissions increase significantly during extreme heat. A 2021 review of studies on climate change and mental health found that heat can exacerbate a range of mental health conditions—including schizophrenia, bipolar disorder, and anxiety—and that older adults and those with dementia are especially vulnerable. 

Also, data shows that people living in low- and middle-income countries may be particularly vulnerable. For example, a 2020 study examining heat-related hospitalizations in 1,814 Brazilian cities found that mental health hospitalizations rose more than three times as much in lower-income cities compared to higher-income ones during periods of rising temperatures (17.2% vs. 5.5%). Similarly, a 2016 study found that the risk of hospitalizations for mental health conditions increased by up to 36% during heatwaves in Northern Vietnam (considered a low- to middle-income country).

3. Heat is linked to higher mortality among people with mental health conditions

The same 2021 review found that heat is linked with higher rates of death for people living with mental health conditions globally, particularly for women and people over 75 years old. 

But heat-related mortality isn’t only a concern for older people with mental health conditions. Indeed, a 2018 study from England concluded that the risk of death increased by 4.9% in people with psychosis, dementia, and substance use disorders for every 1°C increase above a high-heat threshold. But, alarmingly, the highest risk was seen in younger people and those with substance use disorders. 

4. Suicide rates rise with temperature—and may get worse with climate change

A growing body of research links rising temperatures with increased suicide risk. In Finland, for example, temperature variability explained more than 60% of suicide rate fluctuations over 250 years, according to one study. Similarly, a 2018 study using data from the United States and Mexico shows that for every 1°C increase in monthly average temperature, suicide rates increased by 0.7% in the U.S. and 3.1% in Mexico. The researchers estimated that without action, climate change could contribute to over 21,000 additional suicides by 2050.

If you’re experiencing suicidal thoughts or are in danger of harming yourself, this is a mental health emergency. Contact The Suicide & Crisis Lifeline 24/7 by calling or texting 988. Also, if you or a loved one is struggling with your mental health, you’re not alone. Charlie Health’s virtual programs provide compassionate, evidence-based support for people facing serious behavioral and mental health concerns. With flexible scheduling and personalized care, we’re here to support you every step of the way. Complete our quick form to connect with our Admissions Team and begin your healing journey today.