The purpose of this study is to develop an experimental paradigm to examine acute withdrawal symptoms from cocaine.

Although there are clearly identifiable withdrawal syndromes following cessation of a number of abused drugs such as alcohol and heroin, it is unclear whether a withdrawal syndrome follows the cessation of crack cocaine. A laboratory model of withdrawal from smoked (crack) cocaine would provide a safe and systematic method of testing the efficacy of behavioral or pharmacological treatments for withdrawal symptoms following cocaine smoking cessation. Therefore, this study investigated acute behavioral, subjective, and physiological withdrawal symptomatology for 6 hrs following 7 deliveries of 2 dose sized (0.07 vs. 0.4 mg/kg) of smoked cocaine. The behavioral measure was performance on a computerized reaction time task, subjective measures included participant and observer ratings of mood and withdrawal symptomatology, and physiological measures comprised heart rate and blood pressure. It was hypothesized that signs and symptoms of withdrawal from smoked cocaine would be greater following the 0.4 mg/kg dose size, compared to the 0.07 mg/kg dose size.

Inclusion Criteria:

M/F ages 21-45 with a history of smoked cocaine use at least twice a week for the past six months, including 0.5 g of cocaine in a 24hr period on at least one occasion. In good health as evidenced by physical exam and complete blood count, chest X-ray and electrolyte and liver function tests, with a normal resting 12-lead electrocardiograph (ECG) and blood pressure of less than 140/90 mmHg. Using an acceptable method of birth control. Having a urine toxicology screen positive for cocaine metabolites.

Exclusion Criteria:

Any DSM-IV Axis I disorder other than cocaine abuse or dependence, or dependence or daily use of psychoactive drugs other than nicotine or caffeine. A history of violence and/or currently on probation, parole or awaiting trial. Pregnant as determined by serum pregnancy screen, lactating or having delivered a child in the past 12 months. Seropositive tests for the human immunodeficiency virus (HIV) or hepatitis B. History of seizure disorder.