Computer and Therapist Based Brief Interventions Among Cannabis-using Adolescents Presenting to Primary Care: One Year Outcomes

Aims: This paper describes outcomes from a randomized controlled trial examining the efficacy of brief interventions delivered by a computer (CBI) or therapist (TBI) among adolescents in urban primary care clinics.

Methods: Patients (ages 12-18) self-administered a computer survey. Adolescents reporting past year cannabis use completed a baseline survey and were randomized to control, CBI or TBI, with primary (cannabis use, cannabis related consequences - CC) and secondary outcomes [alcohol use, other drug use (illicit and non-medical prescription drugs), and driving under the influence of cannabis (DUI)] assessed at 3, 6, and 12 months.

Results: 1416 adolescents were surveyed; 328 reported past year cannabis use and were randomized. Comparisons of the CBI relative to control showed that at 3 months the group by time interaction (G × T) was significant for other drug use and CC, but not for cannabis use, alcohol use, or DUI; at 6 months, the G × T interaction was significant for other drug use but not for cannabis use, alcohol use, or CC. For analyses comparing the TBI to control, at 3 months the G×T interaction was significant for DUI, but not significant for cannabis use, alcohol use, or CC; at 6 months, the G×T interaction was not significant for any variable. No significant intervention effects were observed at 12 months.

Conclusion: Among adolescent cannabis users presenting to primary care, a CBI decreased cannabis related problems and other drug use and a TBI decreased cannabis DUI in the short-term. Additional boosters may be necessary to enhance these reductions over time.