Cerebral evoked responses in schizophrenia

Results of previous studies of evoked responses in schizophrenic disorders are reviewed, and data from a new study of somatosensory recovery functions in schizophrenia are presented. Subjects in the latter study were 18 schizophrenic patients and 18 nonpatients matched for age and sex. Latencies and amplitudes of eight consecutive evoked-response peaks were measured. Only one amplitude and one latency of the response to the first stimulus discriminated between patients and controls, whereas four amplitudes and three latencies of the second response did so. Amplitude recovery was less in patients, whereas latency recovery was greater. The data verified previous findings of impaired amplitude recovery in schizophrenia, but did not confirm previous findings of increased amplitude in response to a single stimulus. Evoked-response deviations so far determined are not specific to schizophrenic disorders, inasmuch as they have been found in several other psychiatric syndromes. The data are in accord with the idea that psychiatric disorders involve deviant cerebral processing of sensory information.