Long-Term Effect of a Bystander Violence Intervention on Prevalence of Drug Use Disorders in a Prospective Cohort of Emerging Adults

Introduction: Bystander interventions have shown promise to reduce interpersonal violence. Substance use may co-occur with violence; thus, bystander training to identify and intervene in these ‘risky’ situations may additionally reduce substance abuse. Design: Prospective cohort study based on an existing (2010–2014) cluster-randomized controlled trial (RCT) evaluating Green Dot bystander intervention efficacy. Setting/Participants: Kentucky high school seniors (n = 3377) from intervention and control high schools were recruited in three waves to begin cohort surveys during the spring of 2014–2016 and followed from high school into adulthood through 2018. Intervention: Green Dot bystander training in school as randomized (2010–2014) and reported after high school (2014–2018). Main outcome measure: Substance use disorder (SUD, DSM-5 criteria) rates (%) for the past 12 months at baseline (5.1%), 12-month follow up (4.7%), and final follow up (12–48 month; 6.8%) follow up. Results: No statistically significant differences were observed between intervention and control schools at either follow up. However, self-reported receipt of Green Dot bystander training in and after high school was associated with lower substance use disorder (SUD) rates at the 12-months (n = 2078; p =.004) and final follow-up (at 24–48 month; n = 1896; p =.001) relative to those receiving no training. This pattern held for both sexes and among those attending 4-year colleges. Conclusions: Receipt of Green Dot bystander training, in and after high school, may additionally reduce SUD rates. Replication research using prospective cohorts and other bystander training approaches is encouraged.