Multiple measures of hemispheric dysfunction in schizophrenia and depression

Abstract

SYNOPSISElectrodermal, electroencephalographic and perceptual measures of lateral hemispheric function were obtained from groups of chronic schizophrenics, depressives and normals on 2 occasions, separated by 4 weeks. The measures of hemispheric function were derived from previous research. About half of the schizophrenics were medicated on both occasions; the other schizophrenics underwent drug ‘washout’ before the first session. Results revealed that the measures of laterality were not strongly intercorrelated. In the perceptual task, the schizophrenics and normals displayed different laterality effects. Unlike the normals, the schizophrenics' left hemisphere function appeared to be inferior to the right hemisphere function in the perceptual task. The laterality effects of the depressives and normals differed on two electrodermal measures: skin conductance level and skin conductance response amplitude. The depressives' electrodermal activity from the right hand was diminished as compared with the left hand; the normals did not show this effect. Medication decreased electrodermal activity in the schizophrenics, but had no significant effect on laterality. These results suggest that the various measures of laterality used singly in previous research in psychopathology may not all assess the same phenomenon.