Adolescent substance abuse results in significant negative outcomes and extraordinary costs for youths, their families, communities, and society. Moreover, rates of psychiatric comorbidity among substance abusing youth range from 25% up to 82%, and youths with a dual diagnosis have worse outcomes and are more than twice as costly to treat than their counterparts with no comorbidity. This project was a pilot test of a new treatment, OPTION-A, which was adapted from Multisystemic Therapist (MST) and other evidence-based interventions to specifically treat youth presenting for outpatient treatment of comorbid substance use and internalizing disorders. The project was a randomized controlled pilot trial comparing the experimental treatment to usual services in the community.