Cocaine dependence is a major public health problem; an effective primary treatment for cocaine dependent individuals has yet to be found. The purpose of this study is to identify subpopulations and baseline conditions that are most responsive to treatment for cocaine dependent individuals.

Cocaine is a strong central nervous system stimulant that is widely abused throughout the United Sates. Due to its widespread use, it is important to develop an effective treatment for cocaine dependence. Motivational Interviewing (MI) is often effective when combined with drug treatment. Baseline condition (e.g., abstinence status) and population type (e.g., ethnicity and gender) often affect how an individual responds to treatment for drug dependence. The purpose of this study is to determine the influence of baseline status and population type on treatment response in cocaine dependent individuals. In addition, this study will examine how various cocaine abuse medications target different neuronal systems, withdrawal symptoms, and relapse to drug use.

This study will take place in two phases. Phase I will last 4 weeks; participants will receive MI and undergo contingency-based urine tests in order to achieve the desired baseline condition. Phase II will last 12 weeks. Participants in Phase II will be randomly assigned to receive one of four treatments: 1) 50 mg naltrexone, 2) 800/200 mg levodopa/carbidopa, 3) 400 mg modafinil, or 4) placebo. During Phase II, all participants will receive psychotherapy and contingency management. Participants will complete urine drug screening tests 3 times each week. Follow-up study visits will occur between 3 and 6 months following Week 12, and will include objective and self-reported drug use.

• Cocaine Abuse
• Cocaine-Related Disorders

• Drug: Naltrexone
• Drug: Modafinil
• Drug: Levodopa/Carbidopa
• Drug: Placebo

• Experimental: Naltrexone hydrochloride , 50mg per day
• Experimental: Levodopa/carbidopa, 800/200 mg per day
• Experimental: Modafinil 200mg

Inclusion Criteria:

• Meets DSM-IV criteria for current cocaine dependence

Exclusion Criteria:

• Meet diagnostic criteria for other serious psychiatric symptoms and/or disorders that would interfere with participation in the treatment study (e.g., psychosis; mania; suicidal/ homicidal ideation) including other forms of drug dependence, nicotine and cannabis excepted.
• Medical conditions contraindicating naltrexone therapy (e.g., past history of opioid use in the 30 days prior to study entry or significant hepatocellular injury)
• Medical conditions contraindicating modafinil therapy (e.g., hypertension, seizures, arrhythmia, or coronary artery disease)
• Medical conditions contraindicating levodopa/carbidopa therapy (e.g., severe pulmonary/cardiovascular disease, narrow angle glaucoma, melanoma, history of peptic ulcer, or renal function impairment)
• Requires certain medications
• Current or recent treatment for substance use or other psychiatric condition
• On parole or probation that requires reports of drug use to officers of the court
• Pending incarceration
• Pregnant or breastfeeding
• Unable to read, write, or speak English
• Plans to leave the study area within 3 months of study entry