New research links heatwaves to depression and anxiety in adolescents, with some at higher risk

A large-scale study published in the Journal of Affective Disorders has found that adolescents who experienced more intense heatwaves were more likely to report symptoms of depression and anxiety. The associations were strongest in students living in rural areas and among boys, suggesting that heat exposure may not affect all adolescents equally.

The findings come amid growing concerns about the mental health effects of climate change. While past research has shown that extreme heat can impact physical health, this study adds to a smaller but emerging body of evidence linking heatwaves to psychological distress, particularly in young people.

The researchers conducted the study to better understand how environmental stressors like extreme heat might influence mental well-being in adolescents, a group going through major physical, social, and emotional changes. Depression and anxiety are already leading causes of disability among adolescents worldwide, and both are expected to worsen with rising global temperatures. Yet, much of the existing research has focused on adults, leaving a gap in knowledge about how young people are affected.

“As a Chinese scholar, I have observed the increasingly frequent and intense heatwaves in China over the past decade,” said study author Yizhen Yu, a professor at the Tongji Medical College at Huazhong University of Science and Technology.

“As I focus on adolescent public health, I became concerned about how climate change—and specifically, extreme heat—might affect young people’s mental health, a topic that has received little attention compared to physical health impacts. While the physical consequences of heatwaves are well-documented, their psychological effects on adolescents remain understudied. Given adolescents’ unique developmental vulnerabilities and the growing threat of extreme heat events due to climate change, our study aimed to help bridge this important knowledge gap.”

The researchers analyzed data from nearly 20,000 adolescents in China, drawn from a national school-based health survey conducted in 2021. The students, aged 10 to 18, were recruited through a multi-stage sampling process designed to capture variation across geographic regions, school types, and urban-rural settings. After removing incomplete or inconsistent responses, the final sample included 19,852 participants, with roughly equal numbers of boys and girls.

To measure depression and anxiety, the researchers used two widely accepted screening tools: the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder 7-item scale. Students who scored 10 or higher on either scale were considered at risk for depression or anxiety, respectively. Roughly 19% of participants met the criteria for depression, and 16% met the criteria for anxiety.

Heat exposure was assessed using three different definitions of heatwaves. The primary measure was the Excess Heat Factor, which considers both short-term temperature spikes and longer-term trends, allowing for a more nuanced understanding of heatwave intensity and acclimatization. Two additional definitions focused on the frequency of days with high maximum or minimum temperatures, relative to historical averages.

Daily air temperature data for each school’s location were pulled from the ERA5-Land dataset, which offers high-resolution temperature estimates. By geocoding school locations and averaging the heatwave magnitudes over the previous 12 months, the researchers were able to estimate each student’s exposure to heatwaves in their local environment.

The researchers used logistic regression models to examine the relationship between heatwave exposure and mental health outcomes, adjusting for potential confounders such as sex, grade level, region, socioeconomic background, physical activity, and environmental conditions like precipitation.

They found that greater exposure to heatwaves, as measured by the Excess Heat Factor, was significantly associated with higher odds of depression, anxiety, and the co-occurrence of both conditions. For each unit increase in heatwave magnitude, the odds of depression increased by 13%, and the odds of anxiety increased by 12%. The same metric was also linked to comorbid depression and anxiety, as well as to cases where depression or anxiety occurred alone.

“Our findings suggest that exposure to heatwaves is associated with a higher risk of depression and anxiety symptoms among Chinese adolescents,” Yu told PsyPost. “This highlights the importance of recognizing mental health as an integral part of climate resilience, and the need for schools, families, and policymakers to pay special attention to the psychological well-being of youth during extreme weather events.”

When the researchers used alternative definitions of heatwaves—based solely on unusually high daytime or nighttime temperatures—the results were less consistent. These definitions were not as strongly linked to mental health symptoms, especially after adjusting for other variables. This suggests that measures like the Excess Heat Factor, which account for cumulative stress and short-term acclimatization, may be more effective in capturing the psychological toll of extreme heat.

“We found it striking how the association between heatwaves and adolescent mental health varied depending on how heatwaves were defined, highlighting the importance of measurement choice in climate-health studies,” Yu said. “Notably, our findings indicated that male students and those living in rural areas were particularly vulnerable to heat-related mental health risks.”

“These insights have valuable implications for targeted interventions—for instance, improving access to cooling facilities in rural schools, encouraging adaptations for outdoor activities among males, and designing more breathable summer uniforms. Such measures could help protect the most susceptible groups during extreme heat events.”

The study also explored whether certain subgroups were more affected than others. While the associations held across most demographic categories, they were especially pronounced in rural areas. Among students in rural schools, heatwaves were consistently associated with depression, anxiety, and their co-occurrence. In contrast, no significant associations were found for students in urban schools.

Male students also appeared to be more vulnerable to the mental health effects of heat exposure, particularly for anxiety. Among boys, greater exposure to heatwaves was linked to a 22% increase in the odds of experiencing anxiety, while the increase was smaller and not statistically significant among girls. This finding runs counter to the general trend in mental health research, where girls are often found to be more likely to report internalizing symptoms like anxiety and depression.

In sensitivity analyses, where depression and anxiety were analyzed as continuous scores rather than binary outcomes, the results remained consistent. Higher heatwave exposure was linked to higher depression and anxiety scores overall. These results add further support to the observed associations.

As with all research, the study has limitations. Because the data were collected at a single point in time, the researchers could not determine whether heatwave exposure caused the observed mental health symptoms or whether other unmeasured factors were involved.

“As a cross-sectional study, we cannot infer causality, and longitudinal research is needed to confirm these associations,” Yu noted. “Additionally, mental health symptoms were self-reported, which may introduce reporting bias. We were also unable to account for individual adaptive behaviors (such as air conditioning use), which may modulate the effects of heatwaves.”

Despite these limitations, the study offers strong evidence that heatwaves are associated with mental health symptoms in adolescents and that this relationship may vary depending on sex and location. It highlights the need for mental health and education systems to account for the psychological impacts of climate change.

“My long-term goal is to systematically explore how various climatic factors—not just heatwaves, but also cold spells, precipitation patterns, and other climate extremes—affect the mental health and behavioral development of adolescents in China and beyond,” Yu explained. “I am particularly interested in identifying both risk and protective factors, as well as developing and evaluating interventions that can help young people better adapt to the psychological and behavioral challenges posed by climate change. Ultimately, I hope my research can inform public health policies and contribute to the development of school-based programs that support adolescents’ well-being in the face of diverse climate-related risks.”

“Climate change is a growing threat to mental health, particularly for vulnerable populations like adolescents,” Yu added. “It’s crucial not only to raise awareness of these issues but also to empower young people with coping strategies and advocate for their inclusion in climate policy discussions. Policymakers should integrate heat resilience into public health strategies—for example, by revising school safety protocols during heatwaves. Ultimately, meaningful collaboration across health, education, and environmental sectors is essential to protect and promote youth mental health in the face of climate challenges.”

The study, “Associations of exposure to heatwaves with depression and anxiety among adolescents: A cross-sectional study of the Chinese adolescent health survey,” was authored by Jie Hu, Wei Hu, Zixuan Xu, Chang Peng, Junhan Cheng, Fajuan Rong, Yan Wang, Nan Zhang, Meiqi Guan, and Yizhen Yu.