Heat waves: a risk to mental health

The health impacts of climate change are not limited to the physical effects of heat. Mental health is also affected. CERAC’s Belgian Climate Risk Assessment report (BCRA) identifies three main mechanisms:

• The direct effects of high temperatures on mental well-being.
• The psychological impacts of climate-related disasters.
• Anxiety linked to climate change (eco-anxiety).

Heat waves can disrupt sleep, increase stress and exacerbate pre-existing mental health conditions. People with pre-existing mental health conditions, the elderly, or those living in unsuitable accommodation are particularly vulnerable.

Additionally, people living in precarious situations are more vulnerable to mental health problems. At the same time, they often have fewer resources available to adapt to climate change, particularly heat waves. This situation creates a double vulnerability, with existing psychological difficulties being potentially exacerbated by greater exposure to heat.

The available data also show that hospital admissions for mental health conditions are 9.7% higher during heat waves. In Brussels, the cumulative risk of suicide-related mortality was twice as high at an extreme average daily temperature of 24.4 °C compared to the reference temperature of 11.6 °C. However, this does not mean that heat alone causes suicide. Suicide remains a complex phenomenon influenced by numerous factors interacting with each other.

Extreme heat can also exacerbate social tensions. Studies show that heat waves are associated with a rise in domestic and spousal violence. Stress, sleep problems and tension exacerbated by high temperatures are all factors that can increase risks in households.

Floods, fires and other extreme events can lead to anxiety, depression, sleep disorders or post-traumatic stress. These psychological consequences may be due to the loss of housing, property or income, a sense of insecurity and fear, the loss of a loved one, etc. Evacuation and displacement cause additional stress. These effects sometimes persist long after the disaster.

In Belgium, 114 people affected by the 2021 floods were interviewed. More than half reported a deterioration in their psychosocial well-being more than two years after the events.

Loïc Gillerot, health expert at CERAC

This reality is a reminder that reconstruction is not just about infrastructure, but also about restoring security, trust and social ties.

The psychological impact of climate change does not always require direct exposure to a disaster. Simply anticipating the consequences can lead to fear, anger, sadness or a feeling of helplessness. These emotions are often grouped under the umbrella term ‘eco-anxiety’. When they become overwhelming, they can affect sleep, concentration and even quality of life.

Young people seem to be particularly affected. In Belgium, the ‘Eco-Émois’ study shows that about 10% of young people frequently suffer from eco-anxiety, and 57% of 16- to 18-year-olds feel helpless in the face of climate change. Parents seem to underestimate the phenomenon.

Belgium already has mechanisms in place to provide psychosocial support following emergencies. However, the BCRA considers that the overall level of preparedness remains low. The links between climate policy and mental health remain under-explored, and the psychological impacts of heat or disasters are still little monitored.

The BCRA recommends, among others, to integrate mental health into climate adaptation plans, to strengthen long-term psychosocial support following disasters, to improve the follow-up of impacts on psychological well-being, and to ensure that mental health services have sufficient capacity. The development of green spaces can also help to both reduce the effects of heat and promote mental well-being.

How do heat waves impact mental health?

Heat waves can increase stress, sleep disturbances and irritability, and exacerbate existing mental health conditions. Vulnerable people, such as the elderly or those already suffering from mental health problems, are particularly at risk.

Can climate-related disasters have long-term psychological effects?s catastrophes climatiques peuvent-elles avoir des effets psychologiques à long terme ?

Yes. Following a flood, a fire or a storm, some people may develop anxiety, post-traumatic stress or other psychological disorders that persist for several months or even several years after the event.

How can we better protect mental health against climate change?

Better protecting mental health includes adapting to climate-related risks. Strengthening adaptation to heat waves, improving preparedness for extreme weather events and taking psychological impacts into account in adaptation policies help to reduce the population’s vulnerability.