Research on the methamphetamine grant is now centered on the elucidation of the neurochemical and behavioral changes subsequent to the repeated administration of d-amphetamine or methamphetamine. Previous work on neurochemical alterations indicated that permanent depletion of central catecholamines is induced by the repeated administration of high doses of methamphetamine. Ongoing research in this area includes analysis of the underlying mechanism responsible for these depletions. This inludes histological sectioning and analysis of catecholamine synthesis changes as well as recent evidence that another monamine, serotonin, may be equally affected by the treatment with methamphetamine. Behavioral alterations produced by treatment with methamphetamine are being analyzed over a wide range of tasks. These include activity measures, induction of taste aversions and anorexia by methamphetamine, disruption of performance on DRL and fixed interval operant tasks and fine motor control as measured using a force lever. The long-term goal is to provide information on possible neurotoxic and permanent behavioral alterations following the administration of amphetamine.