Impacts of extreme temperatures on mood disorders: A systematic review

Climate change has contributed to an increase in extreme temperatures globally, with mounting evidence suggesting a relationship between extreme temperature exposure and mental health. This review synthesizes findings on the impacts of extreme temperatures on several aspects of mood disorders.

This systematic review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guideline. Major databases (MEDLINE/PubMed, PsycINFO, Scopus, and Web of Science) were searched for eligible studies. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool.

From the 471 identified reports, 22 were included in the final review. The included studies were set in Asia (n = 8), North America (n = 7), Europe (n = 5), and Oceania (n = 2), encompassing diverse designs (case-crossover, cohort, and cross-sectional). High temperatures were linked to increased hospital admissions for mood disorders, especially among adolescents, women, and the elderly. Seventeen studies identified significant correlations between extreme heat and emergency department visits, whereas others reported minimal associations. Short-term exposure to humidity was a risk factor for increased mood disorder symptoms. Extreme cold exposure was associated with increased outpatient visits and heightened symptom severity for depressive disorders, particularly among older adults and females. The included studies were generally of moderate quality.

The evidence from this review underscores the need for multi-pronged interventions, innovative practices, and public health strategies - including urban planning, patients' and public education, use of telemedicine, and policy measures - to mitigate the mental health consequences of climate change-driven extreme temperature events.