Conditions: Cannabis Dependence
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 70
Healthy volunteers: no

Brief summary:
Cannabis is the most widely used illicit drug in the United States, and worldwide, with 1 in 10 users estimated to meet diagnostic criteria for cannabis dependence. Avoidance of withdrawal symptoms (e.g., disturbances in mood, sleep, and craving) is a common relapse precipitant. Cannabis use also impairs executive cognitive functions thereby increasing vulnerability to relapse and reducing the ability to benefit from behavioral therapy. There are no pharmacological treatments for cannabis dependence, despite the large number of afflicted individuals and the limitations of behavioral therapies which do not remediate withdrawal and are associated with high rates of treatment failure. The primary aim of this clinical trial is to evaluate the efficacy and safety of a novel neurokinin1 (NK1) receptor antagonist, aprepitant (Emend), (125mg/day), in outpatients with current cannabis dependence. The main hypothesis to be tested is to evaluate the relative efficacy of aprepitant 125 mg/d vs. placebo for reducing cannabis withdrawal symptoms in cannabis dependent outpatients, specifically anxiety, mood, craving and sleep.

Detailed description:
This study will be a Phase II, single-site, 8-week, randomized, double-blind, placebo-controlled, parallel group comparison of aprepitant (125 mg/d) or placebo. Subjects will be 100 outpatients seeking treatment for current cannabis dependence with no clinically significant medical or psychiatric disorders (including substance use disorders or a positive drug screen for substances other than cannabis or nicotine). All subjects will receive weekly manual-guided abstinence-oriented counseling to facilitate showing a drug effect above and beyond available therapies (Weeks 0-8). Research assessments of marijuana use and withdrawal and drug safety and tolerability will occur weekly through the treatment phase of the 8-week study. Post treatment follow-up assessments will occur at Weeks 9 and 12. Neuropsychological testing will occur at Weeks 0 and 4 and 8.

Specific Aim 1: To evaluate the relative efficacy of aprepitant 125 mg/d vs. placebo for reducing cannabis withdrawal symptoms in cannabis dependent outpatients, including anxiety, mood, craving and sleep symptoms.

Specific Aim 2: To evaluate the relative efficacy of aprepitant 125 mg/d vs. placebo for reducing marijuana use in cannabis dependent outpatients.

Specific Aim 3: To evaluate the relative efficacy of aprepitant 125 mg/d vs. placebo for reducing cannabis related impairments in executive functioning in cannabis dependent outpatients.

Arms:
arm 1: 125mg/d aprepitant for 8 weeks given in conjunction with 8 weeks of manual-guided behavioral counseling. arm 2: Placebo pill daily for 8 weeks given in conjunction with 8 weeks of manual-guided behavioral counseling.

Interventions: intervention 1: Aprepitant intervention 2: Placebo intervention 3: Manual-guided behavioral counseling
Intervention descriptions: intervention 1: 125mg/day for 8 weeks intervention 2: 125mg/d placebo pill for 8 weeks intervention 3: Standardized manual-guided behavioral counseling performed 1 time per week for 8 weeks in conjunction with study drug or placebo.

Protocol document: