Population Mental Health After Acute Collective Stressors: A Cross-Cohort Comparison of Large-Scale Natural and Technological Disasters

Background:  Disasters disrupt both formal and informal organizational and social systems, with impacts extending across the socio-economic spectrum.  Disasters often provide a natural experiment to examine the health impacts of an acute collective stressor on a population.  This cross-cohort comparison assesses the mental health status of three disaster-exposed populations during a mid-term recovery phase, two to three years after the acute collective stressor.  The model controls for a range of disaster exposure, from minimal to severe, and explores the contribution of both formal and informal systems to long-term mental health outcomes.

Methods:  The three randomly sampled cohorts include the Gulf Coast Child and Family Health Study, a longitudinal cohort (n=1079) of displaced and heavily-affected Louisiana and Mississippi adults, post Katrina; the Sandy Child and Family Health Study (n=1,000) a random population sample of an exposed population in nine New Jersey counties; and the Gulf Coast Population Impact Project, a cross-sectional household survey (n=1,437) of residents in four Gulf Coast states exposed to the Deepwater Horizon oil spill.  In-person surveys were conducted 2-3 years after the event.

Findings:  The prevalence of mental health distress varied by cohort, although each independent cohort produced results suggesting enduring mental health effects among exposed populations.  There was a strong association between the magnitude of disaster exposure and mental health effects, independent of lower socio-economic status.

Implications:  Cross-disaster analyses promote generalizability beyond a single disaster.  This analysis illuminates the relationship between organizational and social systems and population mental health.