Marijuana is the most commonly used illicit drug, yet few clinical trials have evaluated
pharmacotherapy treatments for marijuana dependence. This study will evaluate the efficacy of
buspirone for reducing marijuana use in marijuana-dependent adults. A contingency management
(CM) intervention and motivational enhancement therapy (MET) will be incorporated to
encourage study engagement and retention. It is hypothesized that buspirone combined with MET
and CM will reduce the percent of marijuana-positive urine drug screen results in
marijuana-dependent individuals as compared to a placebo treatment combined with MET and CM.