Flood exposure associated with elevated odds of PTSD, depression, and anxiety in affected populations

BACKGROUND: Flooding, intensified by climate change, poses serious risks to lives, infrastructure, and mental health. Conditions such as post-traumatic stress disorder (PTSD), depression, and anxiety are among the most prevalent consequences for affected populations. This study systematically reviews and meta-analyses the evidence on the prevalence of flood-related mental health outcomes and associated risk factors. METHODS: A systematic review and meta-analysis were conducted in accordance with PRISMA 2020. We searched PubMed, ScienceDirect, Scopus, Web of Science, and Embase for studies published 1 January 2004 - 3 June 2024 reporting flood-related PTSD, depression, or anxiety. On 24 September 2025, we performed a citation search of all studies included after the primary search (and key relevant reviews) to identify additional eligible articles published since June 2024. Eligible quantitative studies reporting (or permitting derivation of) odds ratios were synthesised using random-effects meta-analysis to estimate pooled ORs with 95% CIs; where multiple models were available, fully adjusted estimates were prioritised. Subgroup/meta-regression analyses examined sociodemographic and contextual moderators (e.g., time since flood, instrument, region), and sensitivity analyses included leave-one-out and influence diagnostics. Prediction intervals and I were reported; publication bias was assessed where k≥10. RESULTS: Of the 107 studies included in the review, 18 provided data suitable for meta-analysis. Flood exposure was associated with significantly elevated odds of PTSD (OR = 3.01), depression (OR = 2.38), and anxiety (OR = 2.84). Key vulnerability factors included female gender, unemployment, pre-existing mental illness, repeated flood exposure, and severe housing damage. Longitudinal evidence suggested that mental health impacts often persist for years beyond the acute disaster period. CONCLUSIONS: Flood exposure was associated with substantially higher odds of adverse mental health outcomes, with disproportionate effects on vulnerable groups. These findings highlight the importance of integrating mental health support into disaster preparedness, response, and long-term recovery planning.