| Prior research has shown that persons with schizophrenia have impaired cognitive functions that continue years after the acute phase. These deficits affect functional abilities and overall quality of life. While some evidence points to impairment with executive, language, and memory functions, conclusions have been mixed as to the exact nature of these impairments. The present study was conducted to clarify and expand knowledge of cognitive functioning in chronic schizophrenia patients (N = 21) as compared to a bipolar group (N = 20) and a normal group (N = 20).;To examine cognitive functioning, the three groups were administered neuropsychological tests, including the Wisconsin Card Sorting Test (WCST), Trail Making Test (Trails), Controlled Oral Word Association (COWA), Stroop Color and Word Test, California Verbal Learning Test (CVLT), Wechsler Memory Scale-Revised (WMS-R), Rey-Osterrieth Complex Figure (Rey), and Kaufman Brief Intelligence Test (K-BIT). Results of a MANOVA indicated that there were significant differences among the three research groups. Results of a MANOVA, with education and intellectual level as covariates, continued to demonstrate significant differences among the three groups in all but the Stroop Interference task. Neuman-Keuls follow-up analyses indicated the schizophrenia group was significantly different from the normal group on all the neuropsychological variables measured (WCST Categories, WCST Perseverative Errors, Trails B Time T Score, Controlled Oral Word Association Total, Stroop Interference T Score, CVLT delayed free recall, Rey delayed memory, WMS-R logical stories delayed memory). However, no significant differences were found between the schizophrenia and bipolar groups on the Stroop Interference T Score, WMS-R logical stories delayed percentile, and the Rey Figure delayed memory raw score. These results provide continued support of cognitive dysfunction in schizophrenia, specifically impairment in changing cognitive sets, mental flexibility, verbal fluency, and delayed verbal and figural memory. These results also point to frontal and temporal lobe dysfunction in schizophrenia patients. |
