 Cues related to past drug use induce a particular pattern of brain activation, which has been correlated with craving for cocaine in active cocaine abusers. The proposed research is designed to assess the role of dopamine in cue-elicited as well as spontaneous craving for cocaine. Cocaine abusers and control subjects will be presented with a stimulus complex related to drug abuse cocaine cues: videotape depicting drug use, drug paraphernalia or to nature neutral cues: videotape depicting items such as shells and pinecones. The effects of each cue condition on striatal D2-like dopamine DA receptors and changes in intrasynaptic dopamine will be measured by positron emission tomography PET. The PET data will then be correlated with subjective self-reports of mood, particularly measures of craving. These results will be compared between the two subject groups. This research will help clarify the role of dopamine in cue-elicited responses that contribute to cocaine abuse. Ultimately, the results obtained may lead to the development of anti-craving medications. 