Lateralized cerebral dysfunction in schizophrenia and depression: gender and medication effects.

The neuropsychological functioning of 52 schizophrenic and 39 major depressive patients was examined using the four Luria-Nebraska Neuropsychological Battery lateralization scales, with the effects of gender and medication status examined alone and in interaction with diagnosis and laterality variables. Comparisons between the diagnostic groups revealed that gender influences some aspects of neuropsychological performance, particularly those involving bilateral complex cognitive-perceptual rather than sensorimotor skills. This effect was more distinct for depressives than schizophrenics when cerebral lateralization differences were present. There was no significant left hemisphere disadvantage for schizophrenics which was gender-related. Medication status revealed no appreciable effects for depressives, although both male and female schizophrenics receiving neuroleptics showed a greater degree of complex perceptual-cognitive dysfunction compared to unmedicated schizophrenics. Level of cerebral impairment was equivalent for the right and left hemispheres for both groups. Consequently, these data are not consistent with other findings demonstrating differential hemispheric disadvantages between schizophrenia and depression.