Ohio Valley Node-Network (OVNN) of the NIDA Clinical Trials Network

Study Objectives The primary objective of this study is 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 cannabis-dependent adults (ages 18-50). Study Design This is a Phase 3, 12-week, intent-to-treat, two-group, double blind, randomized, placebocontrolled trial with one follow-up visit approximately 4 weeks post-treatment. Eligible participants will be randomized to NAC or PBO. Randomization will be stratified by study site and participant self-reported tobacco smoking status. Study Population Approximately 300 participants will be randomized into this 6-site study (approx. 50 participants per site). The study population will include treatment-seeking cannabis-dependent adults who submit positive urine cannabinoid testing during screening. Individuals with acutely unstable medical or psychiatric disorders or substance dependence aside from cannabis or nicotine will be excluded. Treatments Participants will be randomized to receive orally administered NAC 1200 mg or matched placebo twice daily for 12 weeks. All participants will concurrently receive CE and CM interventions. The CE intervention (weekly during treatment) will emphasize medication compliance, retention, and abstinence, and is designed as a low-intensity platform that encompasses important common elements of psychotherapy targeting substance use disorders, such as empathy, education, and a supportive participant-researcher relationship. CM procedures (twice 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). Assessments Cannabis use outcome measures include self-reported use (Timeline Follow-Back) and urine cannabinoid testing (qualitative and creatinine-normalized quantitative). Secondary measures include, but are not limited to, cannabis craving (Marijuana Craving Questionnaire), cannabis withdrawal (Cannabis Withdrawal Scale), compulsive drug symptoms (Obsessive Compulsive Drug Use Scale), cannabis associated problems (Marijuana Problem Scale), depression/anxiety symptoms (Hospital Anxiety and Depression Scale), sleep quality (Pittsburgh Sleep Quality Index), and quality of life (PhenX Toolkit assessment). Medication adherence will be assessed using self-report, blister pack pill counts, and urine riboflavin testing. Primary Analysis The primary analysis will evaluate the impact of NAC versus PBO on cannabis use during the 12-week treatment intervention. The primary outcome measure is odds of negative urine cannabinoid tests submitted during active treatment, compared between treatment groups. Main Secondary Analysis The main secondary analysis will evaluate the impact of NAC versus PBO on end-of-treatment cannabis abstinence. The main secondary outcome measure is the proportion of participants ineach treatment group submitting consistently negative urine cannabinoid tests during the last two and last four weeks of treatment. Replication Analysis We will additionally conduct the above-described Primary and Main Secondary Analyses with consideration of only the first 8 weeks of treatment, in order to evaluate whether prior adolescent findings (8-week trial) may be replicated in adults.