Quantitative EEG in schizophrenia and in response to acute and chronic clozapine treatment.

Topographic quantitative electroencephalographic (EEG) power and frequency indices were collected in 17 treatment refractory, DSM-III diagnosed schizophrenic patients, before and after acute (single dose) and chronic (six weeks) clozapine treatment, as well as in 17 healthy volunteers. Prior to treatment, patients exhibited greater overall absolute theta power, slower mean alpha frequency and elevated absolute delta and total power in anterior regions. Acute dosing increased total spectrum power globally, slow wave power posteriorally, mean alpha frequency and beta power anteriorally and decreased alpha power posteriorally. Six weeks of clozapine treatment significantly reduced clinical ratings of positive and negative symptoms as well as symptoms of global psychopathology. Chronic treatment resulted in EEG slowing as shown by decreases in relative alpha power, mean beta/total spectrum frequency and by widespread increases in absolute total and delta/theta power. The preliminary findings suggest that brain electric profiling may be a promising tool for assessing and understanding the central impact of pharmacotherapeutic interventions in schizophrenia.