Methods: Contributing to the Adolescent Substance Abuse Treatment Database (ASAT-D), an ongoing effort to comprehensively identify and synthesize intervention research for adolescent substance abusers, the authors searched databases for studies conducted between 1960 and 2008 aiming to reduce adolescent alcohol use. Search criteria included both experimental and quasi-experimental research designs with sufficient information to calculate effect sizes. Study characteristics were recorded independently. Two dyads of authors independently coded studies and interrater agreement assessment showed minimal coding error (Kappa > .75). Hedges's adjusted g for effect sizes was used to correct for sample size bias. Due to dispersion based on clinical inference and supported by statistically significant Q-Values, we could not assume the true effect was identical across studies, and subsequently used a random-effects model.
Results: Findings from 16 investigations published between 1994 and 2008 constituted the final sample. The adjusted pooled effect size for all interventions was -0.61 (95% CI = -0.83 - -.40). The largest effect size was for Motivational Interviewing (g =-1.992, 95% CI = -2.37 - -1.61). Brief Motivational Interviewing, Active Aftercare, Multidimensional Family Therapy, and Brief Intervention with Adolescent and Parent also yielded large effects (>0.80). Effect sizes were larger for individual interventions (g = -0.75, 95% CI = -1.05 - -0.40) compared to family-based interventions (g = -0.46, 95% CI = -0.66 - -0.26).
Implications: Findings indicate numerous treatments for adolescents contribute to the reduction of alcohol use. Three of the five interventions that contained the largest effect sizes were brief interventions. These findings are clinically significant as brief interventions are increasingly required by managed care funding sources. Although both individual-only and family-based interventions were statistically significant, these findings indicate individual approaches had a larger influence on the reduction of alcohol use for adolescents with alcohol use disorders. This finding runs contrary to previous research highlighting family-based interventions as the ideal treatment modality, so this comparison should be assessed further as more research is conducted and disseminated. Finally, when evaluating studies with longer follow-up periods, Behavioral Treatment and Multidimensional Family Treatment are the two interventions that resulted in significant reductions in alcohol use at 12-month follow-up. Considering that these interventions focus on altering maladaptive behaviors, it appears behavioral-based treatment, whether individually- or family-based, is beneficial in attaining long-term change.