RESUMO
OBJECTIVES: Mass violence incidents (MVIs) involving firearms, commonly referred to as "mass shootings" have become increasingly frequent in the United States. These shootings often result in immediate casualties and have far-reaching psychological impacts on survivors, witnesses, and the broader community. This study aimed to assess the prevalence and risk factors of depression within affected communities. STUDY DESIGN: Population-based cross-sectional study. METHODS: Data were collected from six communities affected by MVIs involving firearms that occurred between 2015 and 2020. Participants were randomly selected through address-based sampling, and depression was assessed using Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) diagnostic-level major depressive episode (MDE). RESULTS: Overall, the MDE prevalence was 17·2% since the MVI, 15·4% in the past year, and 8·2% in the past month. Significant risk factors for MDE since MVIs include high exposure to the incident (adjusted relative risk [aRR] = 1·32, 95% confidence interval [CI]: 19-1·60), being aged 18-29 years (aRR = 2·52, 95% CI: 1·61-3·95), being a woman (aRR = 1·58, 95% CI: 1·27-1·96), having low social support (aRR = 1·80, 95% CI: 1·46-2·22), and experiencing past sexual or physical trauma (aRR = 2·20, 1·52-3·19). CONCLUSION: Our study reveals a high burden of depression within communities affected by MVIs involving firearm use. Persons with high exposure to the MVIs and certain demographic groups had greater risks for MDE. These findings highlight the long-term mental health burden in communities affected by MVIs and underscore the necessity of providing mental health services in its aftermath.