Study of the Effects of Risperdal Consta on Brain Reward Circuitry Function, Craving and Cocaine Use in Active Cocaine Dependence

Inclusion Criteria:

• current cocaine dependence who use cocaine at least every 2 weeks
• Non-treatment seekers who intend to continue using cocaine
• Male 18-60 years of age
• Potential participants must be literate in the English language, and be able to understand and complete rating scales and questionnaires accurately
• Able to provide informed consent
• Potential participants must be able to identify at least one "locator" person to assist in tracking the participant for follow-up assessments

Exclusion Criteria:

• Other current substance dependence requiring immediate detoxification
• Diagnosis of schizophrenia, bipolar disorder, current major depressive disorder
• Currently suicidal or at high risk for suicide in the judgment of the investigator
• Carrying a medical device incompatible with MRI (e.g., metal implants such as surgical clips or pacemakers and extensive dental work such as bridges) or suffering from significant claustrophobia that would make MRI unfeasible.
• Size incompatible with MRI procedures
• Serious medical illness including HIV-1 infection
• Hepatitis C + titer with liver enzymes more than 2x normal or a Mini-Mental Status Exam Score of <25/30
• Insulin dependent diabetes mellitus (IDDM) or non- insulin dependent diabetes mellitus (NIDDM) and abnormal Hemoglobin A1C
• Severe hepatic or renal impairment
• History of seizure disorder, delirium, dementia, or mental disorders due to general medical conditions
• History of head trauma or stroke with lasting neurological sequelae
• Tardive dyskinesia, extrapyramidal movement disorder, Parkinson's Disease or history of Neuroleptic Malignant Syndrome
• Clinical or laboratory evidence of uncontrolled hypothyroidism/hyperthyroidism
• Orthostatic hypotension, defined as a decrease of at > 10 mm Hg in systolic blood pressure and/or an increase in heart rate of > 20 beats per minute, measured one minute following transition from a supine to a standing position.
• History of allergy or hypersensitivity to Risperidone
• Treatment with: Neuroleptics, Antidepressants, Antiarrhythmics, Carbamazepine, Phenytoin, Valproate, Rifampin, Phenobarbital, Levodopa and other dopamine agonists, Fluoxetine, Interferon, Propylthiouracil, Methimazole, Opiates.
• Treatment within 30 days prior to screening with an investigational drug or medication with the potential to influence cocaine use outcomes