Project Summary/Abstract: Approximately 10% of adolescents are diagnosed with an alcohol or other drug (AOD) use disorder each year in the U.S. Such disorders increase risk of premature mortality and morbidity and confer negative effects on social and neurocognitive functioning, biobehavioral maturation, and the achievement of developmental milestones. Despite advances in intervention research for adolescent AOD,1-4 the science base, in general, has lagged sorely behind that of adults.5-7 Furthermore, few studies have tested effective treatment models that can sustain youth remission over time as adolescents navigate the high-risk period of emerging adulthood. While many different interventions for youth AOD disorders have been developed and tested producing similar results,1 absent is one that links youth to ubiquitous, freely available, community recovery resources, such as Alcoholics Anonymous (AA) or Narcotics Anonymous (NA). Systematic clinical linkages to these 12-step community resources have the potential to extend and enhance formal interventions’ effects because they have been shown to mobilize the same kinds of therapeutic mechanisms mobilized by formal treatments (e.g., by enhancing motivation/self-efficacy, changing social networks),8, 9 but do so for free and over the long-term in the community.10, 11 The evidence in support of adult participation in these organizations has grown substantially with findings supporting clinic-based Twelve-Step Facilitation (TSF)12-17 interventions and community 12-step group participation12, 18, 19 in enhancing remission rates while reducing health costs.20-22 In more recent years, several naturalistic studies have examined the clinical and public health utility of systematically linking young people with these prevalent resources 23-31 showing long-term benefits from AA/NA8, 28, 30 and in reducing health care costs,31 similar to adults. While dozens of studies have tested adult TSF efficacy,17, 32, 33 until recently, none had tested youth TSF efficacy, despite 80% of youth programs using 12-step practices and linkage.28, 34 In the first NIH-funded study to develop and test a replicable, manualized, adolescent TSF, however, we found that youth randomly assigned to receive a novel combination treatment (Integrated Treatment for Enhancing Growth in Recovery during Adolescence [InTEGRA]) that incorporated key elements of TSF in addition to Motivational Enhancement Therapy/Cognitive-Behavioral Therapy (MET/CBT), showed moderate-large clinically meaningful advantages that grew across follow-ups when compared to youth receiving MET/CBT alone. They also attended two to three times as many 12-step meetings during treatment, with 12-step attendees showing significantly greater abstinence.35 Given initial efficacy and potential for widespread adoption and implementation,34, 36, 37 InTEGRA now needs to be tested in a larger sample, with additional emphases on how (i.e., mechanisms) and for whom (i.e., moderator...