Live updates: Europe hit by brutal, record-breaking temperatures as heat wave intensifies

Extreme temperatures can lead to more violence, with research suggesting crimes like murder, aggravated assault and rape, terrorist attacks and mass shootings are much more likely.

Multiple studies have shown that there’s a direct correlation between high temperatures and hot tempers, and that anger can sometimes lead to bad behavior.

“We don’t like being hot,” said Dr. Curtis Craig, a human factors research associate in the HumanFIRST Laboratory at the University of Minnesota.

“High temperatures increase discomfort. It increases negative emotions, particularly if one has a negative association with something else already.”

Scientist have come up with two theories on why crime might rise during a heat wave. It could be that hot weather induces interpersonal violence by increasing discomfort, frustration, impulsivity, and aggression.

But heat also tends to change people’s routine activities – for example, many are more likely to spend more time outside or drink more alcohol – which could lead to more crime.

Extreme heat can also make mental health problems worse. Dr Laurence Wainwright, senior researcher in the Department of Psychiatry at the University of Oxford, said the relationship between heat and mental health is “complex, nuanced and involves intricate feedback loops between a collection of bio-psycho-social factors.”

“Heat can worsen existing mental health symptoms, manifest new symptoms, and in some conditions like bipolar disorder, act as a trigger to switch into a certain phase of a condition – such as mania,” he said, adding that side effects of many commonly prescribed psychiatric medications can get worse in extreme heat.

Research shows a 10% increase in mental health-related A&E admissions during periods of sustained heat.