Lithium attenuates the activation-euphoria but not the psychosis induced by d-amphetamine in schizophrenia

d-Amphetamine (20 mg) was administered intravenously in a double-blind design to 17 schizophrenic patients with and without concurrent 3-week lithium carbonate pretreatment to evaluate the lithium attenuation of d-amphetamine effects which we had observed in affective disorder patients. Lithium significantly attenuated the acute d-amphetamine-induced changes in an activation-euphoria cluster and in the mannerisms and posturing item of the Brief Psychiatric Rating Scale. Because the psychosis-increasing effects of d-amphetamine were not significantly decreased, it is conceivable that the d-amphetamine-induced changes in activation and euphoria and in psychosis are regulated by different dopamine mechanisms. The small clinical effects seen at 3 weeks of lithium treatment in schizophrenic patients could be mediated by dopamine.