NIDA-CTN-0053

The primary objective of this Phase 3 study is to evaluate the impact of N-Acetylcysteine (NAC) 1200 mg versus matched placebo (PBO) twice daily, added to contingency management (CM), on cannabis use among treatment-seeking cannabis-dependent adults (ages 18-50). The primary outcome measure will be the odds of negative weekly urine cannabinoid tests during active treatment. Primary analysis will be based on an intent-to-treat evaluation of all participants randomized into the study, with missing urine specimens coded as missing and assumed to be positive. Sensitivity analyses will be performed to determine how other procedures for missing data affect results.