(279) The Impact of Extreme Heat on Mental Health Utilization and Prescriptions

Background: : Extreme heat is recognized as a driver of adverse health outcomes, yet its impact on mental health remains underexplored. Prior research shows higher temperatures are linked to increased emergency department (ED) utilization for mental health. Some studies suggest a linear relationship between mental health-related ED visits and suicide, underscoring the severity of these outcomes.

Objective: : This study examined the impact of extreme heat on mental health care utilization and costs across ED, inpatient, outpatient, and telehealth settings. We focused on conditions such as schizophrenia, mood disorders, and nonpsychotic disorders. Additionally, we analyzed prescription fills and costs for antianxiety, antidepressant, and antipsychotic medications.

Methods: : We analyzed claims at the Census tract-week level to estimate Poisson fixed effect regressions, incorporating tract-week, tract-year, and cumulative week effects. This compared unseasonably hot or cold weeks to temperate ones in a tract, while controlling for economic and temporal factors. Our dataset included 35 million individuals across the U.S. with commercial, Medicare Advantage, or Medicaid coverage from 2016 to 2023.

Results: : Our findings reveal that mental health care utilization was more sensitive to extreme heat than general health care. On days when the heat index (HI) exceeded 100F degrees, relative to days in 60-70F HI, mental health-related ED visits increased by 1.4%, compared to a 0.9% rise for all-cause ER visits. Further, associated mental health-related ED costs increased by 2.6% on days over 100F. The increase in cost compared to the relative increase in utilization may suggest the heightened severity of mental health episodes. This effect compounds with additional hot days; a week with temperatures consistently over 100F could see an 18% rise in mental health-related costs and an almost 10% rise in visit counts. The analysis of prescription data reveals complex associations. On unseasonably cold days, weekly fills for anxiety and antidepressants tended to decrease, although these results vary by medication type and overlap in treatment use.

Conclusions: : Our study suggests that temperature extremes may exacerbate mental health conditions, driving an increase in utilization and costs. This underscores the need for adaptive strategies in mental health services to address climate-related risks, such as expanding telehealth options, improving access to mail-order pharmaceuticals, and preparing healthcare systems for surges in mental health needs during extreme weather events.

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