Some (don’t) Like it Hot. Persistent High Temperatures Increase Depression and Anxiety

We study the impacts of high temperatures on milder mental health outcomes using clinical administrative data from a National Health Service of England programme treating anxiety and depression. Leveraging monthly variation in temperatures at the English Clinical Commissioning Group level, we find robust evidence indicating that extremely hot temperatures, i.e. above 34℃, lead to an increase in the demand for mental health support, assessments, and treatments by approximately 10, 15 and 12 per cent, respectively. We also show that when temperature shocks are long-lasting and result in heat waves longer than ten days, the effects are particularly pronounced. These results are not affected by individuals’ adaptive response to similar heat stress experienced in the previous month or year. Our back-of-the-envelope calculation indicates that the monetary health costs associated with heat stress are substantial.