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.