Adolescents' Exposure to Medical Marijuana Ads Is Associated with Future Use

Exposure to alcohol advertising is strongly associated with adolescents' alcohol use. To assess whether a similar relationship exists between exposure to medical marijuana ads and subsequent marijuana use, investigators analyzed data from more than 8000 middle-school students (grades 6–8; 52% Hispanic, 16% white, 17% Asian) involved in a randomized, controlled, longitudinal substance abuse prevention program in California.

During waves 4 and 5 of data collection (2–3 years after the intervention), students were asked about exposure to marijuana ads (“on billboards, in magazines, or somewhere else”) in the past 3 months, use of marijuana in the past month, and intention to use marijuana in the next 6 months. The mean age of respondents at wav…