Neuropsychological differences between young and old schizophrenics with and without associated neurological dysfunction.

Age differences among 134 schizophrenics with associated neurological dysfunction, 160 schizophrenics without such dysfunction, 285 nonschizophrenics with neurological dysfunction and 240 patient controls on the Halstead-Reitan neuropsychological Test Battery (HRB) were examined by splitting subjects at their median ages and performing two way analyses of variance for each HRB component test with diagnosis and age category as the independent variables. In the case of the schizophrenics with neurological dysfunction, significant interactions were found for several subtests of the Wechsler Adult Intelligence Scale (WAIS), and for the Speech Perception, Trail Making and Aphasia Screening Test. In the case of the neurologically intact subgroup, significant interactions were only found for the WAIS Comprehension subtest and Part B of the Trail Making Test. Only WAIS Comprehension produced a significant interaction in the nonschizophrenic group with neurological dysfunction. It was concluded that age differences in neurologically intact schizophrenics were generally comparable to those found in the controls, but that was less the case for the neurologically impaired schizophrenics. Furthermore, this pattern of findings is unlikely to be based upon the presence of associated neurological dysfunction alone, but probably reflects the particularly detrimental effect of compounding schizophrenia with neurological dysfunction.