Importance Mass violence incidents (MVIs) are prevalent in the US and can have profound and long-lasting psychological consequences on direct survivors, but their outcomes among the broader communities where the MVI occurred are unknown.

Objective:

To investigate the prevalence of and factors associated with past-year and current posttraumatic stress disorder (PTSD) among adults in communities that experienced an MVI. Design, Setting, and

Participants:

This cross-sectional survey was completed between February and September 2020 with a household probability sample of adults from 6 communities that had experienced an MVI between 2015 and 2019 Dayton, Ohio; El Paso, Texas; Parkland, Florida; Pittsburgh, Pennsylvania; San Bernadino, California; and Virginia Beach, Virginia. Address-based sampling was used to identify randomly selected households, mail invitations, and select 1 adult per household to complete a self-administered paper or online survey. Data analysis was performed from September to November 2023. Main Outcomes and

Measures:

The primary outcome was presumptive diagnostic-level past-year PTSD and current (past month) PTSD determined using American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5) PTSD criteria.

Results:

A total of 6867 adults aged 18 years or older accessed the website with a description of the study and consent materials. Of these, 5991 (87.2%) agreed to participate and completed the survey, 343 (6.3%) partially completed the survey, and 443 (6.5%) did not meet eligibility criteria or refused to participate. Most of the 5991 respondents were female (3825 individuals [53.5%]) and had a mean (SD) age of 45.56 (17.58) years. A total of 1261 of 5931 individuals (21.0%) reported high exposure to the MVI (either they or a close friend and/or family member was on site during the shooting). Nearly one-quarter (23.7%; 1417 of 5977 participants reporting PTSD) met presumptive DSM-5 diagnostic criteria for past-year PTSD, with 8.9% (530 participants) meeting the criteria for current PTSD. Regression analyses found that being female (odds ratio, 2.32; 95% CI, 2.01-2.68) and having a history of both physical or sexual assault and other potentially traumatic events (odds ratio, 9.68; 95% CI, 7.48-12.52) were associated with the greatest risk of past-year PTSD. Conclusions and Relevance In this survey study of 5991 participants, presumptive PTSD was quite prevalent long after the MVI among adults in communities that have experienced an MVI, suggesting that MVIs have persistent and pervasive public health impacts on communities, particularly among those with prior exposure to physical or sexual assault and other potentially traumatic events. Focusing exclusively on direct exposure to MVIs is not sufficient. Incorporating these findings into screening should improve efforts to identify the individuals most in need of prevention or mental health service after MVIs.