Impact of extreme weather events on mental health in South and Southeast Asia: A two decades of systematic review of observational studies.

Extreme weather events in South and Southeast Asia exert profound psychosocial impacts, amplifying the prevalence of mental illness. Despite their substantial consequences, there is a dearth of research and representation in the current literature. We conducted a systematic review of observational studies published between January 1, 2000, and January 20, 2024, to examine the impact of extreme weather events on the mental health of the South and Southeast Asian population. Quality assessment of the included studies was conducted using the Newcastle-Ottawa Scale (NOS) quality appraisal checklist. The search retrieved 70 studies that met the inclusion criteria and were included in our review. Most were from India (n = 22), and most used a cross-sectional study design (n = 55). Poor mental health outcomes were associated with six types of extreme weather events: floods, storm surges, typhoon, cyclone, extreme heat, and riverbank erosion. Most studies (n = 41) reported short-term outcome measurements. Findings included outcomes with predictable symptomatology, including post-traumatic stress disorder, depression, anxiety, general psychological distress, emotional distress and suicide. Limited studies on long-term effects showed higher mental disorders after floods and typhoons, while cyclone-exposed individuals had more short-term distress. Notably, the review identified over 50 risk factors influencing mental health outcomes, categorized into six classes: demographic, economic, health, disaster exposure, psychological, and community factors. However, the quantitative evidence linking extreme weather events to mental health was limited due to a lack of longitudinal data, lack of control groups, and the absence of objective exposure measurements. The review found some compelling evidence linking extreme weather events to adverse mental health in the South and Southeast Asia region. Further high-quality studies are needed to validate our findings, and future research should focus on investigating the impacts of other types of extreme weather events in this region.