CONTRASTS BETWEEN PATIENTS WITH AFFECTIVE-DISORDERS AND PATIENTS WITHSCHIZOPHRENIA ON A NEUROPSYCHOLOGICAL TEST BATTERY

Objective: This study was designed to ascertain the degree and specifi city of cognitive impairments in patients with schizophrenia and patie nts with affective disorders. Method: Cognitive function was assessed with a neuropsychological test battery in consecutively admitted patie nts with schizophrenia (N=57), unipolar depression (N=29), and bipolar disorder (N=16). Results: The performance of the schizophrenic group was significantly below that of the groups with affective disorders on measures of attention and psychomotor speed, verbal and visual memory , and problem solving and abstraction. IQ was lower in the schizophren ic group and appeared to have deteriorated from a normal premorbid lev el that was not different from that of the affective disorder groups, as determined by the Wide Range Achievement Test-Revised reading test, a putative measure of premorbid intelligence. When IQ was controlled, differences between the groups in problem solving and visual memory r emained. Psychiatric symptoms bad a larger impact on test performance in the affective disorder groups than in the schizophrenic group. Conc lusions: These results suggest that patients with schizophrenia perfor m systematically worse on cognitive measures than patients with affect ive disorders, which is consistent with their generally poorer outcome . The results also indicate that schizophrenia and affective disorders are qualitatively distinguishable in neuropsychological terms, given differences in apparent intellectual deterioration, profiles of cognit ive impairment, and associations between cognitive performance and psy chopathology.