SEX-DIFFERENCES IN NEUROPSYCHOLOGICAL FUNCTION IN NONPSYCHOTIC RELATIVES OF SCHIZOPHRENIC PROBANDS

Some recent studies suggest that men with schizophrenia may have great er neuropsychological deficits than women. It is not known, however, w hether similar sex differences may be present in biological relatives of schizophrenic patients. We evaluated neuropsychological functioning of 54 relatives of schizophrenic patients and 72 normal volunteers. I t was hypothesized that, if sex differences were present, they would b e accounted for largely by deficits in male relatives. We were particu larly interested in three neuropsychological functions that we previou sly identified as putative neuropsychological vulnerability indicators for schizophrenia: (1) abstraction/executive function; (2) verbal mem ory; and (3) auditory attention. There were significant group X sex in teractions for verbal memory and motor function, and trends toward sig nificant interactions for auditory attention and mental control/encodi ng. However, with the exception of motor function, it was the female r elatives who accounted for most of the impairment. A speculative expla nation for the findings is that women may have a higher threshold than men for developing schizophrenia. If so, female relatives might be ab le to withstand greater impairments than men before developing psychot ic symptoms. Consequently, in a sample that was limited to non-psychot ic relatives - as in the present study - there could be over-represent ation of both less impaired men and more impaired women. Alternative e xplanations and limitations of the study are also discussed. (C) 1997 Elsevier Science Ireland Ltd.