Stressful situations and cues associated with cocaine can lead to craving in cocaine dependent individuals. The purpose of this study is to determine whether guanfacine or modafinil are effective in reducing stress and cue induced craving in cocaine dependent individuals.

Stress and cocaine cues produce craving and ultimately relapse in cocaine dependent individuals. This is a randomized, double-blind, placebo-controlled study evaluating the effects of either guanfacine (Tenex) or modafinil (Provigil) on stress and cue induced craving in cocaine dependent individuals. Cocaine dependence will be assessed in adults (ages 18-65) as defined by DSM-IV criteria. If the subject signs the consent form, meets the study criteria and does not meet the exclusion criteria they will be included in the study. Subjects will report to the General Clinical Research Center (GCRC) at the Medical University of South Carolina (MUSC), for an outpatient visit and will receive their first dose of study medication. The following day subjects will return to the GCRC and admitted for the duration of the study (two days and one night). There will be a one-week and a one-month follow-up visit. Subjects will be randomly assigned to one of three treatment groups (guanfacine, modafinil, or placebo). Each subject will also be randomly assigned to either a stress or no-stress subgroup. On the test day (day 3) subjects in the stress group will be asked to perform a speech and a math problem in front of an audience (Trier Social Stress Test, TSST), while the no-stress group will be asked to sit quietly and read. Following these tasks, each subject will be exposed to neutral (control) cues and immediately afterwards the subjects will be exposed to cocaine cues (cocaine paraphernalia). Craving/mood, physiological activity, and endocrine responses, will be assessed at pre-set intervals throughout the testing procedure. The cue reactivity protocol will be repeated on the one-week follow-up visit.

Inclusion Criteria:

Subjects must be able to provide informed consent and function at an intellectual level sufficient to allow accurate completion of all assessment instruments.

Subjects must consent to remain abstinent from all drugs of abuse (except nicotine) during the GCRC admission.

Individuals with alcohol dependence will be excluded because of the profound effects of alcohol withdrawal on the HPA axis however, because of the high comorbidity of alcohol use and cocaine dependence, individuals meeting alcohol abuse criteria will be included.

Subjects must consent to random assignment to stress vs. no stress and drug treatment conditions.

Exclusion Criteria:

Women who are pregnant, nursing or of childbearing potential and not practicing an effective means of birth control. Modafinil inhibits metabolism of steroidal contraceptives via CYP3A4 and can reduce the effectiveness of this type of birth control, female subjects must use one of the following methods of birth control: barrier methods (diaphragm or condoms with spermicide or both), surgical sterilization, use of an intra-uterine contraceptive device, or complete abstinence from sexual intercourse.

Subjects with evidence of or a history of significant hematological, endocrine, cardiovascular (including but not limited to left ventricular hypertrophy, mitral valve prolapse, left bundle branch block, myocardial infarction, and angina), pulmonary, renal, gastrointestinal, or neurological disease including diabetes, as these conditions may affect HPA axis function.

Subjects with any liver function test (LFTs) of greater than two times normal, as compromised liver function can interfere with HPA axis activity (Williams and Dluhy 1987) and may affect drug metabolism.

Subjects with Addison's disease, Cushing's disease or other diseases of the adrenal cortex likely to affect HPA axis function.

Subjects with a history of or current psychotic disorder or bipolar affective disorder as these may interfere with HPA function.

Subjects with current major depressive disorder or post-traumatic stress disorder as these disorders are associated with characteristic changes in HPA axis function.

Subjects receiving synthetic glucocorticoid therapy, any exogenous steroid therapy, or treatment with other agents that interfere with HPA axis function within one month of the time of testing.

Subjects taking any psychotropic medications, including SRI's or other antidepressants, opiates or opiate antagonists because these may affect HPA axis function.

Subjects required to take medications that could adversely interact with study medications, including, but not limited to, azole type antifungals, cyclosporine, warfarin, theophylline, or carbamazepine. Any medications that induce or inhibit CYP3A4 pathways are excluded, as modafinil is metabolized through this enzyme system.

Subjects with any acute illness or fever as this may affect HPA axis activity. Individuals who otherwise meet study criteria will be rescheduled for evaluation for participation.

Subjects who are grossly obese (BMI > 39), as this may interfere with HPA axis function.

Subjects who are unwilling or unable to maintain abstinence from alcohol and other drugs of abuse (except nicotine) prior to the stress task procedure.

Subjects meeting DSM-IV criteria for substance dependence (other than nicotine or cocaine) within the past 60 days.