EEG lateral asymmetries in psychiatric disorders.

A number of EEG studies, including our own, have demonstrated higher levels of activity in both the low (delta and theta) and high frequency (beta 2) bands in the left (dominant) frontotemporal areas of schizophrenic patients compared to controls. Furthermore, our recent studies of power spectral density (PSD) analysis showed that even among schizophrenic patients a differentiation could be made between patients with 'left' hemisphere symptoms (e.g. thought disorder) and 'right' hemisphere symptoms (e.g. anxiety); the former characterized by large amplitude high frequency activity in the left frontotemporal area and the latter by bilateral activity of this type. The implications of these findings are discussed.