ELSEVIER Psychiatry Research: Neuroimaging 67 (1996) 113-122 PSYCHIATRY RESEARCH NEUROIMAGENG Multilead quantitative EEG profile of clozapine in resting and vigilance-controlled conditions Silvana Galderisi*, Armida Mucci, Paola Bucci, Maria Laura Mignone, Mario Maj Department of Psychiatry, Medical School, University of Naples, Largo Madonna delle Grazie, 180138 Naples, Italy Received 14 July 1995; revised 20 January 1996; accepted 28 January 1996 Abstract Clozapine is the prototype of a new class of drugs, referred to as 'atypical antipsychotics'. As a matter of fact, the antipsychotic activity of the drug was not predicted by the first studies with quantitative electroencephalography (QEEG), which actually reported an antidepressant pattern. All previous QEEG studies carried out in healthy subjects used a maximum of four leads, exploring only the posterior quadrants of the scalp. The present article reports findings of a multilead QEEG study carded out in 16 healthy men under resting and vigilance-controlled conditions. Increases in slow (delta, theta, and alpha1) and decreases in fast (alpha2 and beta) activities were found, corresponding to changes described for chlorpromazine-type antipsychotics. These results are compared with those of earlier studies. It is suggested that changes in the beta frequency range vary across subjects, whereas changes in slow and alpha activity are more consistent and critical for defining the QEEG profile of the drug. Keywords: Pharmaco-EEG; Atypical antipsychotics; Healthy subjects; QEEG mapping 1. Introduction Clozapine is considered an atypical antipsy- chotic, as it is devoid of cataleptogenic activity, has a low propensity to produce extrapyramidal side effects and tardive dyskinesia, and does not increase prolactin levels in plasma (Baldessarini and Frankenburg, 1991). In spite of the relatively high risk of agranulocytosis, it is considered the first-choice drug for patients with tardive dyskinesia requiring antipsychotic treatment, and * Corresponding author, Tel.: +39 81 5666504; fax: +39 81 5666523; E-mail: gsilvana@ds.cised.unina.it for those who do not respond to standard neuroleptics (Safferman et al., 1991). In these lat- ter patients, clozapine has an impact on all psychopathological dimensions of schizophrenia (Kane et al., 1988; Meltzer, 1992; Pickar et al., 1992; Breier et al., 1994). Clozapine produces a weak antagonism of striatal dopamine D2 receptors, and a more po- tent blockade of DI, I)4, serotonin 5HT:, hista- mine HI, Ctl, a2, and cholinergic receptors (Fitton and Heel, 1990). In contrast to findings with typical neuroleptics, the antipsychotic activity of elozapine is not correlated to D2 receptor block- ade and is thought to depend on its higher affinity 0925-4927/96/$15.00 © 1996 Elsevier Science Ireland Ltd. All fights reserved PII S0925-4927(96)02883-1