ACUTE EFFECTS OF NEUROLEPTICS ON UNMEDICATED SCHIZOPHRENIC-PATIENTS AND CONTROLS

Acute administration of haloperidol (0.2 mg/kg) produced many more sid e effects in normal controls than in unmedicated schizophrenic patient s. Prior to the neuroleptic challenge, both groups were on the periphe ral monoamine oxidase inhibitor, debrisoquin, for at least 1 week, in order to enhance the relative contribution of CNS catecholamine metabo lites to those measured in both plasma and urine. The patient group ha d higher plasma levels of methoxyhydroxyphenylglycol (MHPG) and homova nillic acid (HVA) and higher urinary MHPG output than controls, but th ere were no effects of haloperidol challenge, compared to placebo chal lenge. In both groups there were significant declines in plasma HVA le vels from 8:30 AM to 12 NOON. These declines were unaffected by the ha loperidol challenge. Explanations for the marked differences in behavi oral effects of haloperidol on patients and controls include the possi bility that dopamine receptor numbers were increased in the brains of the schizophrenic patients.