Signal-to-noise Ratio and Response Variability in Affective Disorders and Schizophrenia

  • Monte S. Buchsbaum
  • Richard Coppola
Part of the The Downstate Series of Research in Psychiatry and Psychology book series (DSRPP, volume 2)


Schizophrenic patients tend to have smaller and apparently more variable evoked potentials (EPs) than normal controls. The amplitude abnormality is consistent with a number of psychological theories of schizophrenia (e.g. Freud, Pavlov, Venables, Broen and Storms, Silverman) characterized by Epstein and Coleman (1970) as assuming that the “basic deficit in schizophrenia consists of a low threshold for disorganization under increasing stimulus input.” While it is difficult to compare specific components in recordings made from different laboratories, there is general agreement that the P100-N140-P200 complex is smaller in schizophrenics, regardless of sensory modality (see review by Buchsbaum, 1977). As predicted by the various theories, reduction in amplitude is particularly marked for high levels of stimulation such as rapid rates of stimulus presentation, high intensity (Landau, 1975; Rappaport, 1975), novel (Roth and Cannon, 1972) or paired stimuli (Shagass, 1976).


Response Variability Research Diagnostic Criterion Average Evoke Response Evoke Brain Potential Research Diagnostic Criterion 
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Copyright information

© Plenum Press, New York 1979

Authors and Affiliations

  • Monte S. Buchsbaum
    • 1
  • Richard Coppola
    • 1
  1. 1.Biological Psychiatry BranchNat. Inst. of Mental HealthBethesdaUSA

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