The purpose of this study was to evaluate the effectiveness and cost-effectiveness of two types of outpatient treatment with and without Assertive Continuing Care (ACC) for 320 adolescents with substance use disorders. Study participants were randomly assigned to one of four conditions: (a) Chestnut's Bloomington Outpatient Treatment (CBOP) without ACC; (b) CBOP with ACC; (c) Motivational Enhancement Therapy/Cognitive Behavior Therapy-7 session model (MET/CBT7) without ACC; and (d) MET/CBT7 with ACC. Based on prior quasi and experimental studies, the investigators hypothesized that MET/CBT would be more effective and cost-effective than CBOP in terms of increasing days abstinent and decreasing substance abuse problems. Additionally, the investigators hypothesized that the groups receiving ACC would have significantly better outcomes than the groups without ACC. Lastly, the investigators hypothesized that adding ACC to MET/CBT would be the most cost-effective option in terms of days abstinent.