The impact of clozapine on electrophysiological features: how can we utilize the findings?

INTRODUCTION : There is a large body of findings on the impact of clozapine upon electrophysiological features. This study repeats several of these earlier studies and reports on whether, and how, these findings can be utilized in our particular research/clinical situation. METHODS : Neurophysiological investigations were carried out on 37 schizophrenia patients, before and after commencing a clinically indicated trial of clozapine. Data from three areas of investigation-EEG, quantitative EEG (QEEG), and evoked response potential (ERP)-were compared with findings from earlier studies. Analysis was also extended to include clinical indicators, dosages, and several novel combinations of features. RESULTS : Our local population has a higher incidence of baseline abnormalities than that found in earlier investigations. Even with this difference, clozapine still leads to an increase in EEG slow-wave activity. The slow-wave increase is significantly correlated with an increase in P3 amplitude of the ERP. While QEEG changes were correlated with clinical changes, the ERP correlation did not reach significance levels. CONCLUSIONS : Electrophysiological findings, particularly from small numbers of studies, may not be generalizable to all populations. Findings which were replicated, however, support the potential use of slow wave changes in the EEG in clinical management. (Int J Psych Clin Pract 2002; 6: 95-102)

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