Teen Marijuana Check-Up

Overview

This study will test a behavioral intervention tailored for adolescents who smoke marijuana and have concerns about their use. The study's purpose is to determine whether this intervention (two-sessions of motivational enhancement intervention followed by 12 months of optional skills training) will be more effective in reducing the use of this drug if augmented by three periodic motivational enhancement treatment check-in sessions as compared to three periodic computer-based check-in sessions. HYPOTHESES: (1) Participants in the motivational enhancement treatment check-ins (MCI) condition will reduce their use of marijuana more than participants in the computer based (Comp) condition and report fewer negative consequences. These differences are expected to be greater at later follow-ups (i.e, 9, 12, and 15 months) after repeated check-ins exert a cumulative effect. (2)Engagement in CBT sessions will be greater for those in the MCI condition and will partially mediate the effect on marijuana related outcome indices. (3) The MCI intervention will lead to increased self-efficacy, and decreased normative perceptions of marijuana use by other teens that will also partially mediate the effect of the intervention.

The goal of this trial is to evaluate the efficacy of an enhanced Teen Marijuana Check-Up protocol to reach and intervene with non-treatment seeking adolescents who use marijuana heavily. Two hundred fifty adolescents who use marijuana heavily will receive a 2-session individual motivational enhancement therapy. All participants will also be offered the opportunity, over a 12-month period, to repeatedly re-initiate marijuana counseling. Participants will be randomly assigned to receive one of two types of periodic follow-up contacts: Motivational interviewing-based Marijuana Check-Ins (MCI) or Computer Based Control (Comp) sessions. All participants will be reassessed at the 6, 9, 12, and 15-month anniversaries of enrollment. Following their initial motivational enhancement therapy, the 125 experimental condition participants will additionally have a motivational enhancement treatment "check-in" session with their counselor at the 4, 7, and 10-month anniversaries of enrollment intended to reinforce the maintenance of treatment gains and motivate continued success, increase motivation to change for participants who did not meet their marijuana use goals, and/or prompt utilization of cognitive-behavioral treatment (CBT) sessions as needed. The 125 comparison participants will complete a computer based questionnaire at the same time intervals to serve as an attentional control.