During the past 15 years, the demand for treatment for marijuana-related problems in the United States has increased nearly twofold. Selegiline is a medication currently used to treat nicotine dependence. The purpose of this study is to evaluate whether selegiline may be useful in treating individuals with marijuana dependence.

Behavioral therapy paired with drug therapy might be a more effective treatment approach to marijuana dependence than behavioral therapy alone. Selegiline is a monoamine oxidase-B inhibitor. It increases dopamine activity in parts of the brain that are involved in dependence on addictive drugs such as nicotine, cocaine, and marijuana. Selegiline has been effective in treating nicotine dependence, but has not yet been studied in treating marijuana dependent individuals. The purpose of this study is to evaluate the effectiveness of selegiline in treating marijuana dependent individuals. Specifically, this study will determine whether selegiline reduces marijuana craving and withdrawal symptoms, thus leading to reduction or abstinence in marijuana use.

Participants in this 9-week, double-blind, placebo-controlled study will be randomly assigned to receive either selegiline (10 mg/day in two 5 mg pills) or placebo. Study visits will occur twice each week. At each study visit, participants will complete self-reports and urine toxicology tests. Throughout the study, participants will receive weekly individual counseling. The counseling sessions will last 15 minutes. Reduction in marijuana use as well as the number of weeks of consecutive marijuana abstinence will be evaluated.

Inclusion Criteria:

• Meets DSM-IV criteria for current marijuana dependence
• Positive urine toxicology test for marijuana
• Reports current marijuana use
• Weighs at least 100 lbs
• Women of childbearing age will be included provided they agree to use adequate contraception

Exclusion Criteria:

• Meets dependence or abuse criteria for alcohol
• Meets dependence criteria for illicit substances other than marijuana
• Serious medical disorders (such as unstable angina or liver failure), that may make participation in the trial unsafe
• Pregnant
• Currently diagnosed with a psychotic disorder
• Currently suicidal or pose a homicidal risk
• Currently taking over-the-counter (e.g., pseudoephedrine) or prescription (e.g., methylphenidate) sympathomimetic agents, antidepressant agents (e.g., tricyclic antidepressants, serotonin reuptake inhibitors, bupropion, other monoamine oxidase inhibitors), or meperidine (Demerol)
• Unable to understand English
• Known hypersensitivity to selegiline hydrochloride