This study represents a randomized, double blind placebo-controlled trial. Thirty cocaine dependant patients will be included in this study during their hospitalization for withdrawal. After the inclusion visit, they will be randomized to receive disulfiram 250 mg/day or placebo over the 15 days of their hospitalization. Main outcome criteria will be evaluated during two TEP imaging sessions with 11Craclopride, before and after stimulation by methylphenidate, 8 to 15 days after randomization. The main outcome criterion will be the variations in linkage rates of 11Craclopride in the nucleus accumbens between baseline TEP measurement and TEP measurement following administration of 20 mg of methylphenidate.