Perceptions of risk and driving under the influence of marijuana and alcohol among a regional census of high school students

BACKGROUND: New state legislation decriminalizing marijuana has brought attention to the issue of driving under the influence of marijuana. We compared how adolescents' perceptions and behaviors differ regarding driving under the influence of marijuana versus alcohol. METHODS: 24,459 students completed the 2012 MetroWest Adolescent Health Survey, a regional census of youth in 26 MetroWest Boston high schools. Students reported perceptions of risk and 30-day passenger behaviors related to riding with a high school driver under the influence of marijuana and alcohol. Bivariate and regression analyses examined associations between perceptions of risk, recent substance use, and passenger behaviors. RESULTS: More students reported riding with a driver who had used marijuana (18.0%) compared with alcohol (10.3%), despite higher recent alcohol use (33.4%) than marijuana use (21.5%). Fewer youth perceived it was “very dangerous” to ride with a driver who used marijuana (52.0%) versus alcohol (77.2%). Among recent marijuana users, 10.8% perceived it was very dangerous to ride with a driver who used marijuana, compared with 63.2% of nonusers. In contrast, 66.5% of recent drinkers perceived it was very dangerous to ride with a driver who had been drinking, with 83.1% of nondrinkers endorsing this perception. Lower risk perceptions were strongly associated with increased reports of risky passenger behaviors for alcohol (AOR=4.6) and marijuana (AOR=7.9), adjusting for substance use, gender, and grade. CONCLUSIONS: Substance use and injury prevention efforts should incorporate strategies to increase risk perceptions related to driving and marijuana, with special efforts targeting students who may use marijuana.