1) To develop a manualized version of an existing, typical traditional martial arts program, modified to target a reduction in substance use and the associated behavioral and psychosocial problems for adolescents in the early stages of substance use or misuse, based on principles derived from empirically-based prevention programs. 2) To obtain preliminary pilot data on recruitment feasibility, validity of assessments, and estimates of the effect size of the intervention in reducing substance use and improving prosocial behavioral and psychosocial outcomes. 3) To refine and further develop the manualized program based on pilot data and utilizing feedback from the initial cohort of participants, traditional martial arts program instructors and substance abuse treatment experts. The goals of these revisions would be to maximize the impact of the program on substance use and behavioral outcomes, while retaining the core features of a traditional martial arts program to ensure the feasibility of implementing, sustaining, and disseminating such a program in existing community-based martial arts programs. 4) To develop procedures for training interventionists (i.e., martial arts instructors and research assistants) and for monitoring program adherence to ensure fidelity. 5) To conduct a small pilot study of the refined manualized program to enable us to estimate the effect size of the intervention and provide information for estimating power for a larger randomized controlled trial should the results of this intervention prove promising in terms of positive impact on the primary and secondary outcome measures: decreased drug use and improvement in psychosocial functioning and behavioral problems (including aggression).