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.Abstract Teaser