 INTRODUCTION. One of the main problems of the treatment of cocaine-dependent patients is the high rate of relapses occurs within the first months after detoxification. In the early withdrawal phase, patients suffer severe anxious depressive symptoms, known in the argot as crash, which occurs in parallel with an appetite overflowed by re-experiencing the effects of the substance, known as craving. Most of the times, these clinical symptoms act as negative reinforcement, which can be severe enough to induce a drug-relapse that greatly hampers the treatment. 