This is a clinical study to evaluate the efficacy of the medication gabapentin in treating persons with cannabis dependence.

This is a 12-week, double blind, placebo controlled study to evaluate the efficacy of gabapentin in treating outpatients with cannabis dependence. After an initial phone screen, a comprehensive screening visit is scheduled to determine eligibility. Upon enrollment, counseling, medication dispensation and research assessments occur 1 time per week for 3 months.

Inclusion Criteria:

• Males or females from 18-65 years of age
• Meets DSM IV criteria for current cannabis dependence
• Seeking research-based outpatient treatment for cannabis dependence that involves daily medication
• Smoked MJ daily at least 25 days per month during the 90 days prior to randomization
• At least a 2-year history of regular MJ use

Exclusion Criteria:

• Abstinent from cannabis more than 2 days at the time of randomization
• Active suicidal ideation
• Currently meets DSM IV criteria for abuse or dependence on other substances, or has urine drug screen positive for substances, other than cannabis or nicotine
• Significant medical disorders that will increase potential risk or interfere with study participation,
• Sexually active female participants with childbearing potential who are pregnant, nursing or refuse to use a reliable method of birth control
• Meets DSM IV criteria for a major AXIS I disorder other than cannabis and nicotine dependence,
• Inability to understand and/or comply with the provisions of the protocol and consent form
• Treatment with an investigational drug during the previous month
• Sensitivity to study drug as evidenced by adverse drug experiences with gabapentin or its ingredients
• Ongoing treatment with medications that may affect study outcomes