Anxiety and depression among survivors 5 years after the Lushan earthquake: a large cross-sectional clinical diagnostic study

OBJECTIVE: Earthquakes represent cataclysmic stressors threatening long-term mental health, yet delayed clinical prevalence remains underinvestigated. This study aims to delineate the weighted 12-month and lifetime prevalence of anxiety and depressive disorders and associated risk factors among Ya'an adults (≥ 15 years) five years post-Lushan earthquake. METHODS: In 2019, a two-phase cross-sectional epidemiological survey of 8,876 individuals utilized a multistage stratified random sampling method. Phase 1 used screening questionnaires; Phase 2 involved formal SCID-5-RV diagnostic interviews. We applied inverse probability weighting, FDR-adjusted Rao-Scott chi-square tests, and weighted multivariate logistic regression. Sensitivity analyses additionally incorporated PTSD and social support to evaluate potential residual confounding. RESULTS: Weighted 12-month and lifetime anxiety prevalence rates were 4.52% and 5.14%. For depression, rates were 3.55% and 4.28%. Adjusted logistic regression identified female gender (adjusted OR [AOR] = 1.52), middle-aged status (AOR = 2.25), and chronic illnesses (AOR = 2.95) as significant anxiety risk factors. For depression, risk factors included female gender (AOR = 1.92), elderly status (AOR = 2.45), chronic illness (AOR = 4.15), and residence in severely (AOR = 1.95) or extremely affected areas (AOR = 1.82). Crucially, severe earthquake exposure remained a robust, independent predictor of depression even after sensitivity adjustment for PTSD and social support (AOR = 1.62). CONCLUSIONS: Five years post-disaster, regional prevalence rates have stabilized near national averages. However, women, elderly individuals, and those with chronic illnesses remain highly vulnerable. The persistent elevation of depression in severely affected zones, independent of individual trauma symptoms, underscores the profound long-term impact of seismic disasters, necessitating targeted, sustainable mental health interventions.