This project involves investigation of oral N-acetylcysteine (NAC) as a potential pharmacologic agent for treatment of cannabis dependence in adolescents. Cannabis dependence continues to be a major problem among adolescents in the United States. To date, psychosocial interventions have produced only small to modest effect sizes in controlled trials, and minimal work has been done to investigate the potential role for pharmacotherapy for cannabis dependence. Translating preclinical research suggesting a role for NAC in cocaine dependent individuals, our research group has developed preliminary evidence of decreased cocaine use and cue reactivity in humans taking NAC. Preclinical research has additionally demonstrated significant parallels in glutamatergic dysfunction in the nucleus accumbens (the proposed target of NAC treatment) between habitual cocaine and marijuana users. NAC is an inexpensive, long-available agent with a favorable tolerability profile in adults and children. However, it has not yet been studied in cannabis dependent adolescents. Hence, we are undertaking an open-label pilot trial of NAC in adolescents with cannabis dependence.