Frontal intermittent delta activity in schizophrenic patients receiving antipsychotic drugs

FIRDA was found in 14 EEGs recorded from 338 schizophrenic patients receiving antipsychotic drugs, although they showed no FIRDA in the baseline EEG. The daily dose of antipsychotic drugs when FIRDA was found was larger than when FIRDA disappeared. FIRDA was assumed to be induced by relatively high doses of antipsychotic drugs. Thus, the effect of antipsychotic drugs should be added to the list of differential diagnoses associated with FIRDA. FIRDA did not correlate with the baseline psychopathology of schizophrenic patients. Patients without FIRDA tended to respond poorly to antipsychotic drugs in terms of negative symptoms. Improvement of positive symptoms in FIRDA patients was not as remarkable as in patients without FIRDA.