EFFECT OF A HALOPERIDOL CHALLENGE ON REGIONAL BRAIN METABOLISM IN NEUROLEPTIC-RESPONSIVE AND NONRESPONSIVE SCHIZOPHRENIC-PATIENTS

Objective: The CNS metabolic response to a neuroleptic challenge in tr eatment-responsive and nonresponsive schizophrenic patients was measur ed in order to examine the relation between treatment outcome and the capacity to alter neurochemical function in response to acute receptor blockade. Method: Positron emission tomography (PET) and [F-18]fluoro deoxyglucose (FDG) were used to measure regional cerebral metabolism i n seven schizophrenic patients judged to have been responsive to drug treatment previously and seven nonresponsive schizophrenic patients af ter a drug-free period of at least 3 weeks (baseline) and again 12 hou rs after administration of 5.0 mg of haloperidol. Results: The haloper idol challenge caused widespread decreases in absolute metabolism in t he nonresponsive patients but not the responsive patients. These group differences reflect the findings on the second (challenge) scans, sin ce metabolic values at baseline were not statistically different in th e two groups. The pattern of decreased metabolic activity in the nonre sponders after the haloperidol challenge is similar to that previously observed in normal subjects. Conclusions: The metabolic response to d rug challenge separates treatment responders from nonresponders and no rmal subjects. The results suggest that subtyping of schizophrenia (an d other psychiatric disorders) can be achieved by measuring the physio logic response to a pharmacologic challenge in vivo with chemical brai n-imaging techniques.