Patterns of neuropsychological deficits that discriminate schizophrenic individuals from siblings and control subjects.

Previous research on persons with schizophrenia and their relatives suggests two independent etiologic factors may combine to produce schizophrenia, and these factors may be indexed respectively by independent neuropsychological tests. Two neurocognitive measures, the Trail Making and Wisconsin Card Sorting (WCST) tests, were administered to 28 schizophrenic subjects, 15 nonschizophrenic siblings, and 35 control subjects by investigators blind to DSM-III-R diagnoses. Results support key predictions of a two-factor model: 1) having poor scores on both tests discriminated schizophrenic individuals from both siblings and control subjects, and 2) poor Trail Making and WCST performance were inversely associated among schizophrenic individuals' non-schizophrenic siblings.