Introduction: The long-term mental health impact of disasters is still poorly understood. This multilevel meta-analysis aimed to assess the impact of the number of fatalities while simultaneously controlling for multiple factors. The objective was to verify whether there is an association between the extent of fatal casualties during a disaster and the mental health impact on exposed populations. Methods: Medline, PsycInfo, PTSDpubs, Web of Science, and SocINDEX were searched for studies published from January 1946 to July 2024 (PROSPERO 2020, CRD42020108528). Longitudinal data from 71 studies (76 disaster-exposed samples) were extracted and augmented with fatality data sourced from Wikipedia. Fatality categories (10,000), disaster type (natural vs. human-made), category (e.g., earthquakes, floods, terrorist attacks), mental health outcome (e.g., post-traumatic stress disorder, depression, anxiety, grief, suicidality), population age groups, disaster year, measurement month, study quality, and country income were included in the analysis. Results: The pooled average prevalence of mental health problems was 21.81% (95% CI 10.07-40.98). From months 1 to 300, the post-disaster mental health burden decreased after an initial peak in the first months, followed by a second peak before declining again (p < 0.001). The prevalence of mental health problems did not differ significantly between mental health outcomes, disaster types or categories, population age groups, disaster year, study quality classification, or country income context. When controlling for these factors, fatality categories (reference: <10) had no significant effect on mental health. The proportion of fatalities differed between income groups. In 67% of disasters in upper-middle-income countries, fatalities exceeded 10,000, while 63% of disasters in high-income countries had fewer than 100 deaths. Conclusion: Although this controlled multilevel meta-analysis demonstrates that the mental health impact of disaster exposure is profound and long-lasting, it did not confirm that a more excessive number of fatalities was related to increased mental health problems.
Dückers et al. (Sun,) studied this question.