Electroencephalographic similarities between chronic alcoholics and chronic, nonparanoid schizophrenics.

We compared the EEG power spectral density patterns for chronic, nonparanoid schizophrenics and age-matched chronic alcoholic and control subjects. Bilateral precentral (F-T) and postcentral (C-O) derivations were used in the analysis. The nonparanoid schizophrenics and alcoholics showed increased low-frequency activity (0 to 6 Hz) in all derivations in comparison to the control subjects. Chronic alcoholics were found to have increased high-frequency activity primarily in the precentral derivations. Nonparanoid schizophrenics showed increased power in the high-frequency bands predominantly in the left precentral derivation. We discuss the implications of patterns of differences concerning the issue of nonspecificity of the EEG in psychiatry.