Dimensional complexity of EEG brain mechanisms in untreated schizophrenia.

The dimensional complexity of left temporal-parietal and parietal-occipital electroencephalographic (EEG) recordings was assessed by computing the correlation dimension during 20 sec in six recording conditions from 15 first-episode acute schizophrenics before medication, 12 other medication-free individuals clinically and socially remitted after a first schizophrenic episode, 17 medication-free neurotics and 17 controls. The correlation dimension of the temporal-parietal EEG differed between groups [analysis of variance (ANOVA)] (p < 0.004), whereas neurotics (different from schizophrenics at p < 0.002) and remitted schizophrenics showed intermediate values. There was no overall significant difference between groups in the parietal-occipital EEG. Differences of the correlation dimension of the temporal-parietal versus the parietal-occipital EEG were significant between groups (ANOVA p < 0.05); first-episode schizophrenics differed from controls (p < 0.002) and remitted patients (p < 0.08). Increased dimensional complexity of schizophrenic EEG was found in one of two examined brain regions. The higher dimensional complexity of functional brain mechanisms in schizophrenics versus normals is reminiscent of the loosened organization of thought, and of suggestions of certain superior abilities in the patients.