Multilead quantitative EEG profile of clozapine in resting and vigilance-controlled conditions

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 carried 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.