It was the aim of our study to examine the interhemispherical and extrahemispherical integration that is possibly disturbed in patients suffering from schizophrenic psychoses, using an easy method of EEG performance spectral analysis. For this purpose, the EEG at rest and the functional EEG were determined in 69 schizophrenic patients (ICD) and 22 healthy subjects and the EEG reactivity was calculated. Differences especially in alpha-2 reactivity were seen both intrahemispherically and interhemispherically. This supports the concept of left hemispheric dysfunction in patients suffering from schizophrenic psychoses.