The purpose of this study is to identify the neurophysiologic indicators of cocaine or methamphetamine use and withdrawal, to examine the relationship between subjects' reports of depression, craving, and stimulant use, and neurophysiologic measures, and to identify neurophysiologic measures which can be used to identify new treatments for stimulant dependence.

By Incorporating QEEG into clinical trails, the plan is to develop physiologic markers of treatment efficacy, and to aid in the identification of effective treatments.

Inclusion Criteria:

M/F ages 21-50. Meet DSM-IV criteria for cocaine dependence. Agree to conditions of the study and sign informed consent.

Exclusion Criteria:

Psychiatric disorder that requires medication therapy. History of seizures. Pregnant and/or nursing women. Dependence on ETOH or benzodiazepines or other sedative/hypnotics. Acute hepatitis. Other medical conditions that deem participation to be unsafe.