CLOZAPINE EFFECTS ON GLUCOSE METABOLIC-RATE IN STRIATUM AND FRONTAL-CORTEX

Eighteen patients with schizophrenia had cerebral metabolic rates asse ssed with positron emission tomography during a double-blind, placebo- controlled crossover study of clozapine treatment. Relative metabolic rates were increased in the basal ganglia, especially on the right sid e. In the frontal lobe, metabolic rates were lowered, more on the left than on the right. The anterior nuclei of the thalamus also showed lo wer metabolic rates after clozapine. We have previously observed patie nts with schizophrenia to have low metabolic rates in the basal gangli a and to lack the normal right > left asymmetry; in this study, clozap ine normalized striatal activity. In the frontal lobe, asymmetry was n ormalized, but hypofrontal function was, if anything, exaggerated. Thi s effect in the frontal lobe was not observed with haloperidol in earl ier studies. The cortical effects of clozapine may be related to its u nique clinical properties and suggest important differences between ty pical and atypical antipsychotic drugs.