FRONTO-STRIATO-THALAMIC PERFUSION AND CLOZAPINE RESPONSE IN TREATMENT-REFRACTORY SCHIZOPHRENIC-PATIENTS - A TC-99M-HMPAO STUDY

Several studies with functional and structural brain-imaging technique s support the hypothesis that responders and non-responders to clozapi ne could show a different pattern of cerebral dysfunction. Thirty-nine neuroleptic-refractory schizophrenic patients were studied with Tc-99 -labelled hexamethyl-propylene-aminoxime (HMPAO) and SPECT, while on c lassical neuroleptics and after 6 months of treatment with clozapine. The perfusion differences between responders and non-responders to clo zapine were studied in the regions included within the dorsolateral an d orbitofrontal fronto-striato-thalamic circuits, as well as the predi ctive value of these parameters. These values were compared to those o f a normal database, and between both treatments within the two groups . On-neuroleptic perfusion in non-responders was lower in the thalamus , basal ganglia and dorsolateral prefrontal cortex. Thalamus and right prefrontal perfusion regions were selected as response predictors by a discriminant analysis. Thalamic and left basal ganglia activities wh ile on neuroleptics were lower only in non-responders with respect to the normal subjects. Perfusion changes were only observed in the respo nder group in thalamus and basal ganglia. Study of regional perfusion may contribute to the prediction of clozapine response. (C) 1997 Elsev ier Science Ireland Ltd.