EEG characteristics in depression, "negative" and "positive" schizophrena.

OBJECTIVE qEEG investigations present differences in the comparison of schizophrenic patients and healthy examinees, as well as of depressive patients and healthy controls. The comparison of "positive" and "negative" schizophrenia also presents differences in the qEEG parameters. Changes in qEEG are various in these studies, but not always consistent. In this research we wanted to compare "positive" schizophrenia, "negative" schizophrenia and depression. SUBJECTS AND METHODS The sample comprised 55 examinees (all women): 20 patients with "positive" schizophrenia, 15 patients with "negative" schizophrenia and 20 patients with depression. The standard EEG registration was done in all of them. From the recorded material, the 20-second period without artifacts was analyzed by the FFT method. The results were presented as absolute special power values (muV(2)) for individual segments of the spectrum: delta (0.5-4.0), theta (4.0-8.0), alpha (8.0-13.0) and beta (13.0-30.0). The observed regions included Fp1, Fp2, F3, F4, F7, F8, T3, T4, P3, P4, O1 and O2. RESULTS The "positive" type schizophrenia differs from the "negative" in the increase in both delta and theta activities, and in the decline of beta activity over frontal regions. The "positive" type of schizophrenia differs from depression in the increase in delta activity over frontal regions, while the "negative" form of schizophrenia differs from it in the decrease in beta activity over frontal regions. CONCLUSIONS qEEG parameters differ in the comparison of "positive" and "negative" types of schizophrenia. These differences are more numerous and more significant than those obtained in the comparison of each of these types of schizophrenia with depression.