Achieving Cannabis Cessation -- Evaluating N-Acetylcysteine Treatment (ACCENT)

Kevin Gray, MD
Lead Investigator

Institute of Psychiatry
Medical University of South Carolina (MUSC)

This is a 12-week, intent-to-treat, randomized controlled trial to evaluate the impact of N-Acetylcysteine (NAC) 1200 mg versus matched placebo (PBO) twice daily, added to compliance enhancement (CE) and contingency management (CM) interventions, on cannabis use among treatment-seeking adults (ages 18-50) with cannabis use disorders.  Approximately 300 participants will be randomized to receive NAC 1200 mg or matched placebo twice daily for 12 weeks.  All participants will concurrently receive CE and CM interventions.  CM procedures (weekly during treatment) will include escalating schedules of cash reinforcement with resets, targeting (a) retention/adherence, and (b) cannabis abstinence (confirmed by negative qualitative urine cannabinoid testing).  The primary analysis will evaluate the impact of NAC versus PBO on cannabis use during the 12-week treatment intervention with the primary outcome measure being the odds of negative urine cannabinoid tests submitted during the 12-week treatment, compared between the two treatment groups. 


The NAC and placebo groups did not differ in cannibis abstinence to a statistically significant degree. Overall, 22.3% of urine cannabinoid tests in the NAC group were negative, compared with 22.4% in the placebo group. Many participants were medication non-adherent; however, exploratory analysis within the medication-adherent subgroups revealed no significant differential abstinence outcomes by treatment group.

In contrast with significant prior findings in adolescents, there is no evidence that NAC 1200mg twice daily plus CM is differentially efficacious for CUD in adults when compared to placebo plus CM.

Primary Outcomes Article: Gray KM, et al. A Randomized Placebo-Controlled Trial of N-acetylcysteine for Cannabis Use Disorder in Adults. Drug and Alcohol Dependence 2017;177:249-257. [get article]



Publications about CTN-0053 (NCT01675661)

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Supported by a grant from the National Institute on Drug Abuse to the University of Washington Alcohol and Drug Abuse Institute.
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Updated 7/2017 --