This study aims to test the preliminary efficacy of 3.0 mg of guanfacine (GFC) daily versus placebo in cocaine and/or alcohol dependent individuals. This proposal is a laboratory and treatment outcome study to examine the effects of guanfacine on brief exposure to stress, drug cues and neutral situations on cocaine/alcohol craving, mood and neurobiological reactivity in a sample of cocaine and/or alcohol dependent individuals. Guanfacine will be beneficial for reduction in stress and drug cue induced craving and related arousal. In a sample of 60 cocaine and/or alcohol dependent men and women, we propose to examine (a) differences in measures of cocaine craving, emotion state, hypothalamic-pituitary-adrenal (HPA) activation, physiological arousal and plasma catecholamine response to stress imagery and to drug cue imagery as compared to neutral imagery; (b) reduction in cocaine/alcohol abstinence symptoms; and (c) improvement in cocaine and alcohol treatment outcomes as measured by increasing abstinence, reduction in cocaine/alcohol use and increased treatment attendance. Hypothesis 1: Guanfacine will decrease stress-induced cocaine craving, negative emotions and related arousal in the laboratory as compared to placebo. Hypothesis 2a: As compared to the PLA group, the GFC group will show significant reductions in protracted withdrawal symptoms as measured by the CSSA/CIWA during the 9-week treatment period.

Hypothesis 2b: As compared to the PLA group, a higher percentage of the GFC patients will remain abstinent during the 9-week treatment period with a higher percent of negative cocaine urines and alcohol-free days.

Hypothesis 2c: The GFC group will show greater adherence to treatment as measured by the days in treatment as compared to the Pla group.