Effectiveness of sequential brief interventions for tobacco and marijuana use among 18-24 year olds

The prevalence of cigarette smoking (36%) and marijuana use (19%) among 18-24 year olds is higher than in any other age group in the US. Since 69% of young adult marijuana smokers also smoke cigarettes, there is reason to believe that the behaviors should be approached concomitantly. Using a two phase design, the aim of this RCT was to evaluate the effectiveness of sequential brief interventions (BI) for tobacco and marijuana use. The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) was used to identify young adults for tobacco and risky marijuana use. 317 18-24 year old cigarette smokers scoring in the moderate risk level for marijuana use were recruited from a federally qualified dental clinic in inner-city Hartford, CT. Phase I: All participants received smoking cessation counseling (including 2 booster calls). Phase II: Participants were randomized into a control group, BI for marijuana use or BI plus 2 additional sessions of MET counseling for marijuana use. For both phases, the main outcomes were the ASSIST Tobacco and Marijuana Scores. Following smoking cessation counseling, participants' Marijuana Scores were significantly reduced from 20.11 (9.32) to 17.86 (9.93), n=268. Following brief intervention for marijuana use, there were no significant changes in the participants' Marijuana or Tobacco Scores for either treatment condition compared to the control group at the time of the two month follow-up (n=178) or six months later (n=174). The significance of the findings for clinical interventions is that opportunistic brief interventions with young adult marijuana users may not be effective.