This chapter outlines the clinical approaches tested and preliminary findings from the Cannabis Youth Treatment (CYT) study. The purpose of CYT was to test the clinical and cost-effectiveness of a variety of interventions targeted at reducing or eliminating marijuana use and associated problems in adolescents. Family support network (FSN) was designed as an adjunct to the 12-week motivational enhancement therapy/cognitive behavioral therapy-12 (MET/CBT12). FSN is based on the belief that a single treatment modality, possibly regardless of duration, is neither intensive nor comprehensive enough to reduce a persistent and multifaceted problem such as adolescent substance use disorders. Adolescent community reinforcement approach (ACRA) therapists help adolescents recognize that their drug use is incompatible with other short- or long-term reinforcers. The theoretical bases of multidimensional family therapy (MDFT) reside in several areas. Individual, family, social, and environmental risk and protective factors are considered as contributing to or buffering against substance use.