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Mental Health, Violence, and Heat Waves

Prevention is better than a cure.

Key points

  • Links between heat-humidity and violence due to mental health and well-being conditions have been examined.
  • Some possibilities exist, although direct, linear, cause-and-effect is nuanced.
  • Violence prevention, for people with and without mental health conditions, would sever many possible links.

India and Mexico have been baking in temperatures above 45°C. The northern hemisphere is moving into summer, wondering if countries might reach this heat level. Meanwhile, the debate continues: Do heat-humidity combinations lead to violence due to mental health and well-being impacts? The answer, as always, is complicated.

Mental health and violence

Research reveals possibilities for mental health and well-being conditions being directly affected by heat and humidity. Examples examined include dementia, depression, and schizophrenia. Some medications for mental health and well-being conditions impede the body’s ability to adjust to heat and humidity. The effectiveness of others changes with body temperature.

Ilan Kelman
Some people (who can) use heat to relax.
Source: Ilan Kelman

Additionally, our bodies respond biochemically to heat and humidity, physically stressing us. This stress can compound to affect us mentally.

Some work therefore concludes that people respond violently in heat waves, whether to others or to themselves via self-harm and suicide. When we are physically and mentally stressed in heat-humidity, or when a heat wave exacerbates mental health and well-being conditions, then a presumption can be that violence must increase.

Preventing violence

One question regarding this reasoning is about the role of prevention. We can have plenty of lead time for episodes of heat and humidity if warning and alert systems are in place. Aside from summer appearing every year, heat waves are generally forecast days in advance with occasional possibilities flagged over longer time periods.

If our health systems fully served people with mental health and well-being conditions exacerbated by heat-humidity, then these warnings would permit risk reduction, prevention, planning, and preparedness. Options could be adjusting medications or their dosages, providing care and support to make it through the excessively hot-humid episode, and offering breaks from work and other activities to stay cool and relaxed.

For others physically and/or mentally stressed from heat-humidity, society ought to provide ways of coping, adjusting, and improving. From mental health and well-being charity phone lines and online chat options through to medical appointments and treatment, while destigmatizing mental health and well-being conditions, again it means having a functioning society that respects healthcare and provides the resources for it.

After all, most of us learn to and prefer to avoid daily aggression and violence. Those who transgress are meant to be dealt with by society’s systems of laws and justice. The reality is that not everyone has access to a solid education, inside and outside of schools, alongside equal, equitable, and fair encounters with laws and justice.

These circumstances are not related to heat or humidity. They are about society, including resource and power distribution.

Imagine if someone kills their spouse or robs a stranger and says, “Yes, I did it. It was particularly hot and humid, so it was really about the weather. In fact, let’s blame climate change, so I am not responsible”. Conversely, many justice systems have provisions for people with mental health and well-being conditions who commit crimes, seeking to support them in improving rather than locking them away without adequate mental healthcare.

The more that such efforts pivot toward preventing violence, the less we have to explain that society has failed both the perpetrator and the victims. These prevention efforts ought to be resourced, no matter what the outdoor air temperature or its trends.

It is the standard mantra that prevention is better than cure. Better for avoiding violence and better for everyone, with or without diagnosable conditions, who swelters in the heat and who is understandably mentally stressed by it.


Florido Ngu, F., I. Kelman, J. Chambers, and S. Ayeb-Karlsson. 2021. “Correlating heatwaves and relative humidity with suicide (fatal intentional self-harm)”. Scientific Reports, vol. 11, article 22175.

Kelman, I., S. Ayeb-Karlsson, K. Rose-Clarke, A. Prost, E. Ronneberg, N. Wheeler, and N. Watts. 2021. “A review of mental health and wellbeing under climate change in small island developing states (SIDS)”. Environmental Research Letters, vol. 16, article 033007.

Romanello, M. and co-authors. The 2023 report of the Lancet Countdown on health and climate change: the imperative for a health-centred response in a world facing irreversible harms. The Lancet, vol. 402, no. 10419, pp. 2346-2394.

Voyatzis-Bouillard, D. and I. Kelman. “Do Climate Change Interventions Impact the Determinants of Health for Pacific Island Peoples?” The Contemporary Pacific, vol. 33, no. 2, 466-496.

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