This study will involve three sequential experiments. Experiment 1 will evaluate the physiological and behavioral effects of various combinations of cocaine and aripiprazole. Experiment 2 will evaluate the capability of aripiprazole at reducing the stimulating effects of cocaine. Lastly, Experiment 3 will evaluate the role of cocaine priming doses on subsequent cocaine use and how aripiprazole might alter the effect of the priming dose. In turn, these findings may lead to future clinical trials using aripiprazole to treat cocaine addiction and prevent relapse.