Prevalence of mental disorders in adult populations from the Global South following exposure to natural hazards: a meta-analysis.

Abstract

Although natural hazards (e.g., tropical cyclones, earthquakes) disproportionately affect developing countries, most research on their mental health impact has been conducted in high-income countries. We aimed to summarize prevalences of mental disorders in Global South populations (classified according to the United Nations Human Development Index) affected by natural hazards. To identify eligible studies for this meta-analysis, we searched MEDLINE, PsycINFO and Web of Science up to February 13, 2024, for observational studies with a cross-sectional or longitudinal design that reported on at least 100 adult survivors of natural hazards in a Global South population and assessed mental disorders with a validated instrument at least 1 month after onset of the hazard. Main outcomes were the short- and long-term prevalence estimates of mental disorders. The project was registered on the International Prospective Register of Systematic Reviews (CRD42023396622). We included 77 reports of 75 cross-sectional studies (six included a non-exposed control group) comprising 82,400 individuals. We found high prevalence estimates for post-traumatic stress disorder (PTSD) in the general population (26.0% [95% CI 18.5-36.3]; I2 = 99.0%) and depression (21.7% [95% CI 10.5-39.6]; I2 = 99.2%) during the first year following the event, with similar prevalences observed thereafter (i.e., 26.0% and 23.4%, respectively). Results were similar for regions with vs. without recent armed conflict. In displaced samples, the estimated prevalence for PTSD was 46.5% (95% CI 39.0-54.2; k = 6; I2 = 93.3). We furthermore found higher symptom severity in exposed, versus unexposed, individuals. Data on other disorders were scarce, apart from short-term prevalence estimates of generalised anxiety disorder (15.9% [95% CI 4.7-42.0]; I2 = 99.4). Global South populations exposed to natural hazards report a substantial burden of mental disease. These findings require further attention and action in terms of implementation of mental health policies and low-threshold interventions in the Global South in the aftermath of natural hazards. However, to accurately quantify the true extent of this public health challenge, we need more rigorous, well-designed epidemiological studies across diverse regions. This will enable informed decision making and resource allocation for those in need.