Brain Imaging Studies of the Effects of Cocaine Abstinence

Inclusion Criteria: Inclusion criteria include: 1. Subjects must be male or female and English speaking. 2. Subjects must be adults with a history of diagnosis of cocaine dependence disorder (n=20) who are under supervised treatment for dependence or normal control (n=10). 3. Subjects must be between 21 to 65 years of age. Exclusion Criteria: Exclusion criteria include: 1. Suicidality or psychosis. 2. Head injury, kidney or bladder disease or any unstable or serious medical conditions. 3. Prior exposure to radiation (including diagnostic or treatment x-rays), which might cause subjects to exceed standard guidelines. 4. Unwillingness or inability to adhere to the requirements of the study. 5. Donation or large loss of blood (\>400 ml) within the past month. 6. Current or very recent illnesses, painful conditions or other disorders, which in the judgment of the investigators, might invalidate the scientific goals of the study or pose undesirable difficulties or risks for subjects. 7. Pregnancy or breast feeding. 8. Individuals who would be unable to undergo a magnetic resonance imaging (MRI) scan, for example, individuals who suffer from claustrophobia, or who have metal clips in their body, metallic prostheses (i.e., replacement body parts, such as a hip joint), a pacemaker, or other pieces of metal in their body (shrapnel, metal filings, etc.).