Inclusion Criteria:

1. Males and females, 18-55 years old
2. Meets DSM-IV criteria for Cannabis Dependence
3. History of chronic cannabis use of moderate intensity defined by 10 or more years of use with an average frequency of 2 or more joints/day on 5 or more days/week
4. Live within a commutable distance of the Treatment Research Center
5. Understand and sign the informed consent
6. Voluntarily seeking treatment for cannabis dependence

Exclusion Criteria:

1. Current DSM-IV diagnosis of any psychoactive substance dependence other than marijuana, or nicotine dependence
2. Concomitant treatment with sedative hypnotics, opioid analgesics or other known CNS depressants at a dose and frequency that is unacceptable to the principal investigator
3. Mandated to treatment based upon a legal decision or as a condition of employment
4. Current severe psychiatric symptoms, e.g. psychosis, dementia, acute suicidal or homicidal ideation, mania or depression requiring antidepressant therapy, or which could make it unsafe for the patient to participate in the opinion of the primary investigators
5. History of significant, unstable heart disease, including myocardial infarction, unstable angina, cardiac failure, second or third degree heart block, uncontrolled hypertension, syncope
6. Known hypersensitivity to cannabinoids or sesame oil
7. Any serious medical illness, which may require hospitalization during the study (i.e. sickle cell anemia, rheumatoid arthritis)
8. Has any disease of the gastrointestinal system, liver or kidneys which could result in altered metabolism or excretion of the study medication (history of major gastrointestinal tract surgery, gastrectomy, gastrotomy, bowel resection, etc.) or history of chronic gastrointestinal disorders (ulcerative colitis, regional enteritis, or gastrointestinal bleeding)

9. Female subjects who are pregnant or lactating, or female subjects of child bearing potential who are not using acceptable methods of birth control.

   Acceptable methods of birth control include:

   Barrier (diaphragm or condom) with spermicide, Intrauterine device, Levonorgestrel implant, Medroxyprogesterone acetate contraceptive injection, Oral contraceptives.

10. Clinical laboratory tests (CBC, blood chemistries, urinalysis) outside normal limits that are clinically unacceptable to the principal investigators. On EKG, 1st degree heart block, sinus tachycardia, left axis deviation, and nonspecific ST or T wave changes are allowed. Liver function tests (LFT's) <5 times ULN without symptoms of liver disease are acceptable after thorough medical review.

Additional Neuroimaging Exclusion Criteria:

Subjects who are selected for the clinical trial based on above inclusion and exclusion criteria will be screened further with the following exclusion criteria for possible participation in the fMRI imaging session:

1. Participation in a clinical trial and receipt of investigational drug(s) other than this clinical trial during previous 60 days.
2. History of serious head trauma or injury causing loss of consciousness that lasted more than 3 minutes.
3. Presence of magnetically active prosthetics, plates, pins, broken needles, permanent retainer, bullets, etc. in subject's body (unless a radiologist confirms that its presence is unproblematic). An X-ray may be obtained to determine eligibility.
4. Claustrophobia or other medical condition disabling subject from laying in the MRI for approximately 60 minutes