As climate change triggers record-breaking heatwaves, wildfires, and floods across the globe, experts are warning of a deepening and underreported crisis: the growing toll on mental health.

“Climate change can have a profound effect on mental health through both direct and indirect pathways,” said Dorina Cadar, a leading researcher in neuroepidemiology and dementia. 

“One in every four children and pregnant women are suffering from malnutrition. On a daily basis, we admit around 25 malnutrition cases."

Cadar said that extreme weather events such as floods, wildfires, and heatwaves are linked to acute stress, anxiety, depression, and post-traumatic stress disorder (PTSD).

Neil Jennings, a climate expert at the Grantham Institute for Climate Change at Imperial College London, said the issue has long been neglected.

“Climate change is having an impact on health-related outcomes … (in) both physical health and mental health,” he said. “But mental health historically has received less attention than physical health.”

Heatwaves and suicide risk

Recent weeks have seen parts of the Mediterranean, Europe, Asia, the US, and the Middle East scorched by prolonged heatwaves. 

Experts say the mental toll is intensifying.

“Heat waves are often overlooked in terms of mental health research, yet these have been linked to changes in mood, increased aggression, disturbed sleep, and a rise in hospital admissions for people with existing mental health conditions,” said Cadar, who directs the Cognitive Epidemiology, Dementia, and Ageing Research (CEDAR) lab at Brighton and Sussex Medical School.

Jennings noted a direct link between extreme heat and suicide. 

“We know that for every 1 °C increase in temperature, there is roughly a 1% increase in the risk of suicide,” he said.

He pointed to research showing that each 1 °C rise in monthly average temperature led to a 2.2% increase in mental health-related deaths. Increases in humidity also drove up suicide rates.

Jennings highlighted the vulnerability of outdoor workers such as laborers, construction workers, and farmers. 

“Farmers, for instance, often experience significant psychological stress due to crop losses from extreme heat, floods, and wildfires,” he said.

Lasting psychological damage

Experts say floods, hurricanes, and wildfires leave lasting trauma.

“The emotional shock of losing one’s home or being displaced, combined with the slow and difficult recovery process, can leave a lasting psychological impact,” said Cadar. “Studies have reported PTSD rates as high as 30% in flood-affected populations.”

Wildfires are linked to increased anxiety, depression, and substance use, especially among evacuees and first responders. Their unpredictability and rapid spread contribute to psychological distress.

Even droughts, though less dramatic, create chronic stress and hopelessness among communities reliant on agriculture. “They also lead to chronic stress, hopelessness, and suicidal thoughts, particularly among farming communities whose livelihoods depend on climate-sensitive environments,” Cadar said.

Who is most at risk?

Cadar said older adults, particularly those with dementia or cardiovascular conditions, face high risks during heatwaves due to limited mobility and difficulty accessing help.

People with pre-existing mental health conditions are also vulnerable, as many struggle to detect or respond to heat-related symptoms. Children, adolescents, and low-income individuals in poorly insulated housing or without access to cooling systems are similarly at risk.

“High temperatures can worsen symptoms of depression, anxiety, and other psychiatric disorders, and may even increase the risk of suicide,” said Cadar.

“This is partly because heat affects the body’s ability to regulate stress and maintain mood balance, but also because many psychiatric medications interfere with the body’s natural cooling processes, making people more vulnerable to heat-related illness.”

Jennings added that “individuals with existing mental health conditions are two to three times more likely to die during extreme weather events.” He pointed to the 2021 heat dome in North America, noting that “about 8% of the people who died had schizophrenia.”

Mental health inequality worsens

Experts also warned that the burden of climate-linked mental health issues falls hardest on the most vulnerable.

“The long-term stress of living with environmental degradation, the threat of losing homes or suffering severe damage, rising temperatures, or worsening air quality can slowly wear away at people’s psychological well-being,” said Cadar.

She noted rising cases of “climate anxiety” or “eco-anxiety,” particularly among younger people and those who feel powerless to stop environmental collapse.

Cadar also linked climate change to disruptions in housing, healthcare, agriculture, and social structures that further damage psychological resilience. “When people lose their livelihoods … are forced to relocate, or feel disconnected from their communities or natural environment, their mental health can suffer,” she said.

“People in disadvantaged or marginalized groups are often hit hardest, as they have fewer resources to adapt and recover.”

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