Development of a motivational interviewing/acceptance and commitment therapy model for adolescent substance use treatment

Introduction: Current adolescent substance treatment models have important limitations. Motivational interviewing (MI) combined with Acceptance and Commitment Therapy (ACT) may be a promising new approach. The purpose of this study is to develop a manual-standardized MI/ACT intervention for evaluation in future controlled trials. Methods: Participants were 41 adolescents and young adults (ages 12-26 years) consecutively admitted to an urban adolescent substance treatment program and the six therapists who administered the intervention. The intervention was 12 weeks of individual, outpatient, manual-standardized MI and ACT combined with contingency management and psychiatric consultation as needed. The outcome measures were the Outcome Rating Scale (ORS), patient satisfaction questionnaires, proportion of days used non-nicotine substances, qualitative interviews of therapists and the Session Rating Scale (SRS). Wilcoxon signed-rank and paired t-tests were used to determine significant change in pre-and post-intervention measures. Results: A total of 14 of 23 (61%) youth with pre-intervention ORS scores in the clinical range had end of treatment scores in the non-clinical range and a clinically significant increase of over 5 points. The proportion of youth reaching a week of abstinence was 71% by self-report and 68% by urine drug screen. The proportion of days used at pre-intervention (Mdn = 1.0; IQR 0.4, 1.0) for those with non-zero pre-intervention use (N = 27) was significantly different at post-intervention (Mdn 0.1; IQR 0, 1.0) (S = 84, p = 0.0014). The average SRS score was 37.9 (SD = 2.2), indicating a high level of satisfaction. Conclusion: This study demonstrates the initial feasibility of using an MI/ACT model in adolescent substance treatment. A small-scale, randomized controlled trial of MI/ACT is needed to evaluate the feasibility of larger, controlled trials and to determine the sample size that will be needed for an adequately powered study.