The proposed research will focus on investigating the determinants and consequences of CAD via measurement of physiological, behavioral and subjective effects of physiologic and psychologic stress cues in CAD volunteers in the laboratory, and through examination of the effects of the effects of Aprepitant, an NK1 antagonist, on the above effects. This study will examine the effects of the above stress cues on cocaine and alcohol craving under acute Aprepitant dosing, and under placebo conditions. The study is a within-subjects crossover design using 24 subjects.