Central dopaminergic activation is hypothesized to underly schizophrenia and, paradoxically, stimulant euphoria. Four cocaine abusers with histories of stimulant-induced paranoid psychoses reported selective reduction in psychotic symptoms but not euphoria when treated with dopamine blockers. This provides preliminary evidence against efficacy of neuroleptics in cocaine abuse prevention, and suggests euphoria and paranoia may have discriminable neurophysiological substrates.