Electroencephalographic findings with low-dose clozapine treatment in psychotic parkinsonian patients

Twenty patients with Parkinson's disease (PD), who developed delusions and psychotic behavior, underwent electroencephalogram (EEG) recordings before and during treatment with low-dose clozapine. Resolution of the psychotic features was observed in all cases. The EEG was unaltered in 15, whereas five patients exhibited increased generalized or focal slowing when compared with the pretreatment tracings. These findings contrast with the high incidence of EEG abnormalities, including epileptiform activity, which are observed when larger doses of clozapine are used in schizophrenic patients, but they underscore that even in low doses, clozapine may cause EEG changes.