A pioneering study led by IDIAPJGol highlights that during periods of extreme heat, diagnoses of anxiety and depression increase in primary care, as well as medical prescriptions and sick leave due to these disorders.
The increase in ambient temperature could be responsible for one in four new diagnoses of anxiety and one in six of depression, according to a pioneering study led by the Institut d’Investigació en Atenció Primària Jordi Gol (IDIAPJGol). The study, recently published in the academic journal Environment International, analyzed data from more than three million adults treated in primary care centers in Catalonia between 2011 and 2022, taking into account differences by sex, age, nationality, and socioeconomic status.

The study concludes that the rise in temperature could be responsible for 25% of new diagnoses of anxiety, 15% of anxiolytic prescriptions, and 31% of sick leaves due to this condition, as well as 17% of new cases of depression, 9% of antidepressant prescriptions, and 25% of sick leaves due to this diagnosis.

More cases on extremely hot days

The study points out that during periods of high temperatures, compared to a temperature of 1 ºC, there are increases of 43% in anxiety diagnoses, 26% in depression diagnoses, and up to 65% more sick leaves due to anxiety. In addition, prescriptions for anxiolytic medication increase by nearly 20% during these periods of extreme heat.
The cases analyzed are included in the database of the Information System for Research Development in Primary Care (SIDIAP), which collects clinical information corresponding to 75% of the population treated in primary care in Catalonia. Of the more than three million people analyzed, 11.7% had an anxiety diagnosis, of which 32.3% had a prescribed anxiolytic treatment and 4.9% had been granted a sick leave. On the other hand, 4.2% of the people included in the analysis had been diagnosed with depression, of whom 20.1% were receiving antidepressant treatment and 0.9% had a sick leave.

Public health policies

This article highlights that exposure to high temperatures is a risk factor for the psychological well-being of the population. IDIAPJGol researcher Andrea Pistillo, the first author of the article, emphasizes that “the increase in ambient temperature should be considered a triggering factor for mental disorders and should be taken into account in public health policies to address the climate emergency, which is associated with an increase in the frequency and intensity of heatwaves.”

Study reference

Pistillo A, Giuliodori A, Palomar-Cros A, Gallo E, Aragonès E, Ballester J, Marí-Dell’Olmo M, Basagaña X, Duarte-Salles T. High temperature and mental health in 3.3 million adults living in Barcelona metropolitan area: a 12-year time series analysis of primary care data. Environ Int. 2025;203:109748. doi:10.1016/j.envint.2025.109748.