Prazosin, a specific alpha1-noradrenergic receptor antagonist, has no effect on symptoms but increases autonomic arousal in schizophrenic patients

The specific α₁-noradrenergic antagonist, prazosin, was administered to seven schizophrenic patients in a double-blind, placebo-controlled trial. Patients showed no change in any of their psychiatric symptoms as rated by nurses on global depression and psychosis scales and by physicians on the Brief Psychiatric Rating Scale. However, they did show a significant increase in autonomic arousal as measured by changes in skin conductance. The increased autonomic arousal is probably mediated by increases in plasma norepinephrine induced by chronic prazosin treatment.