Differences of cerebral lateralization among schizophrenic and depressed patients.

Conjugate lateral eye movements (LEMs) have been used as a measure of contralateral frontal hemisphere activation when individuals carry out reflective tasks. In a previous study, schizophrenics were noted to produce significantly more R-LEMs than controls suggesting that they use the left hemisphere in general more often than controls when initiating thought. More specifically, schizophrenics initiated thought on spatial emotional material in their left hemisphere more often than normals. In an effort to replicate these findings, the present study contrasted a new sample of 13 schizophrenics first with the original schizophrenic sample, and then with 13 psychotic depressives, and the original controls. In addition, other group comparisons are reported. The data obtained replicate the original findings of increased R-LEM (i.e., increased left hemisphere activity) and the excessive processing of spatial and to a lesser extent emotional material in the left hemisphere of schizophrenics. Psychotic depressives were found to initiate reflective tasks more often in their right hemisphere than either schizophrenic or the original sample of normal controls. Significant group differences among schizophrenics, normal controls, and psychotically depressed patients were obtained. The data are consistent with emerging concepts of a left hemisphere locus of disturbance in schizophrenia and right hemisphere disturbances in affective disorders.