Neuroleptic Treatment of Schizophrenic Patients: How Do Haloperidol and Clozapine Normalize Brain Blood Flow Patterns Associated with a Difficult Tone Recognition Task?

Abstract

Chronic treatment with haloperidol causes increased regional cerebral glucose utilization in the basal ganglia (caudate and putamen) and thalamus. In contrast, haloperidol treatment also diminishes metabolic rates in parts of the medial dorsal frontal cortex and the anterior cingulate (Holcomb et al. 1996). It is not known to what extent these chronic changes are responsible for acute, phasic changes associated with specific behaviors. Relatively few studies have examined the impact of neuroleptic medication on metabolic activity patterns of schizophrenic patients engaged in effortful decision-oriented tasks. Cohen (Cohen et al. 1987, 1988, 1992) determined that treated patients exhibited normalized frontal lobe metabolism/behavior relationships. Normal subjects and neuroleptic treated patients exhibit a strong positive relationship between frontal lobe metabolism and the number of correct responses on a tone recognition task (presentation loudness level). Unmedicated patients exhibit no relationship between glucose metabolism and task behavior for frontal brain regions. This and other studies suggest that neuroleptic treatment modifies the relationships between a brain region’s neural activity and the behavior of the subject.