A systematic review of the effectiveness of brief interventions with substance using adolescents by type of drug.

The aim of this paper is to evaluate the effectiveness of brief interventions (BI) with adolescents (mean age <20) in reducing alcohol, tobacco or other drug (ATOD) use by means of a systematic review of BI for adolescent substance use in the English language literature up to 2002. We identified 11 studies involving 3734 adolescents. Follow-up ranged from 6 weeks to 24 months. Motivational interviewing was the predominant approach, underpinning eight studies: the remaining three provided personalized health information. Seven papers reported outcomes for alcohol interventions and four involved other substances (including one with separate alcohol outcomes). The overall effect size was d=0.126 with borderline homogeneity (Q=14.9, df=9, p=0.09). The effect size from the eight alcohol interventions (n=1,075) was classified as significant but "small" (d=0.275). The remaining non-alcohol studies were considered separately as interventions involving tobacco or multiple substance use. The two interventions with tobacco involved a substantial sample (n=2,626) but had a very small effect (d=0.037), while the two interventions addressing multiple substances involved few participants (n=110) but had a medium-large effect (d=0.78). Across a diverse range of settings (dental clinic, schools, universities, substance treatment centres) and, therefore, probably diverse clients, BI conferred benefits to adolescent substance users. BI had a small effect on alcohol consumption and related measures. The data for tobacco interventions suggested a very small reduction, particularly with general community interventions. The effect of BI with multiple substances appears substantial but the small sample cautions against expansive generalization.