Ambient Heat and Risk of Emergency Department Visits for Mental Health among Adults in the United States

Abstract

BACKGROUND AND AIM: Ambient temperature has long been thought to play a role in the exacerbation of symptoms for many mental and behavioral disorders. However, the impacts of elevated temperature on specific mental health outcomes remain poorly documented. Accordingly, we sought to quantify the association between heat and mental health-related emergency department (ED) visits in the conterminous US among adults aged 18 years and older with commercial health insurance. METHODS: We analyzed de-identified data from ~3.5 million ED visits involving a psychiatric diagnosis during the warm seasons from 2010 and 2019 among adults aged 18 years and older with commercial health insurance living in 2,987 US counties using the OptumLabs® Data Warehouse. We estimated daily population-weighted county average maximum ambient temperature (May to September), and evaluated the association between warm-season ambient temperature and specific mental health diagnoses, as well as any diagnosis among those examined, using a case-crossover study design with a distributed lag nonlinear model. RESULTS:We found monotonic increases in the odds ratio (OR) of ED visits associated with any mental health diagnosis. A 10°C increase in temperature was associated with an OR for any mental health ED visits of 1.042 (95% confidence interval [CI]: 1.036, 1.047). Associations with a 10°C increase in temperature were also pronounced for ED visits due to specific illness, including anxiety and stress disorders (OR: 1.039; 95% CI: 1.030, 1.049), mood disorders (OR: 1.033; 95% CI: 1.024, 1.042), substance abuse disorders (OR: 1.049; 95% CI: 1.041, 1.058), and schizophrenia (OR: 1.049; 95% CI: 1.025, 1.074). CONCLUSIONS:We found that in this large population of insured adults in the US, elevated temperature exposures are associated with increased mental health-related emergency department (ED) visits. Future work should aim to further characterize the relationship between sustained periods of extreme temperature (i.e., heat waves) and mental health. KEYWORDS: Temperature, Climate, Epidemiology, Mental Health