Neuropsychological laterality indices of schizophrenia: interactions with gender

Neurobehavioral laterality indices were examined across motor, sensory, language versus spatial, and verbal memory versus spatial memory domains for 75 patients with schizophrenia (45 men, 30 women) and 75 demographically matched healthy controls. Patients were impaired across tasks, and laterality results varied by domain. There was no evidence for diagnosis by hemisphere interactions in motor, sensory, or memory tasks. However, patients were more impaired in language than in spatial domains, which suggests relatively greater left hemisphere dysfunction. This finding was mediated by the sex of the participant. While patients as a group showed greater language than spatial impairment, male patients showed expected superiority in spatial relative to language performance, whereas female patients performed the same on both functions. These results underscore the importance of examining sex differences in laterality effects. The findings also demonstrate that, although the left hemisphere model of schizophrenia may be partially supported by data on higher cognitive functions, this support does not extend to more basic motor and sensory domains.