Study of Quetiapine Treatment for Cannabis Dependence

Conceptually, the pharmacodynamic and clinical actions of quetiapine suggest that it may be
useful for cannabis dependence. By antagonizing dopamine, quetiapine may interfere with the
reinforcing effects of cannabis, while serotonin type 2A, histamine type 1, and adrenergic
receptor antagonism may reduce cannabis withdrawal symptoms, primarily by sedating and
anxiolytic effects. The proposed research project is an open-label pilot study to evaluate
the tolerability and ideal target dosing range for quetiapine treatment of cannabis
dependence over an eight-week period. The purpose of this pilot study is to obtain
preliminary data regarding the potential efficacy, tolerability and safety of quetiapine
treatment of cannabis dependence before conducting a larger double-blind trial.

Inclusion Criteria:

1. Between the ages of 18-65

2. Meets DSM-IV criteria for current cannabis dependence

3. Seeking treatment for cannabis dependence

4. Reports using cannabis an average of five days per week over the past 28 days

5. Capable of giving informed consent and complying with study procedures

Exclusion Criteria:

1. Lifetime history of DSM-IV diagnosis of schizophrenia, schizoaffective disorder, or
bipolar disorder

2. Current DSM-IV criteria for any other psychiatric disorder that may, according to the
investigator's judgment, require either pharmacological or non-pharmacological
intervention over the course of the study

3. Receiving prescribed psychotropic medication

4. Known history of allergy, intolerance, or hypersensitivity to quetiapine

5. Pregnancy, lactation, or failure to use adequate contraceptive methods in female
patients who are currently engaging in sexual activity with men

6. Unstable medical conditions, such as poorly controlled diabetes or hypertension, which
might make participation hazardous

7. Current DSM-IV diagnosis of substance dependence other than cannabis or nicotine
dependence

8. Are legally mandated to participate in a substance use disorder treatment program

9. Increased risk for suicide

10. Diabetes (whether controlled or not), hyperglycemia (fasting glucose > 100 mg/dl),
obesity (BMI > 30) and elevated lipids (cholesterol > 200 mg/dl; triglycerides > 150
mg/dl).