COGNITIVE-FUNCTIONING IN LATE-LIFE SCHIZOPHRENIA - A COMPARISON OF ELDERLY SCHIZOPHRENIC-PATIENTS AND PATIENTS WITH ALZHEIMERS-DISEASE

Objective: Previous studies have suggested that geriatric inpatients w ith chronic schizophrenia manifest profound cognitive impairments. Thi s study investigated how these cognitive impairments resemble those se en in degenerative dementing conditions. Method: The neuropsychologica l battery of the Consortium to Establish a Registry for Alzheimer's Di sease (CERAD), widely used to characterize the cognitive deficits of p atients with Alzheimer's disease, was used to compare patterns of cogn itive impairment in 66 triads of subjects consisting of one elderly pa tient wish Alzheimer's disease, one elderly, institutionalized patient with chronic schizophrenia, and one elderly, cognitively normal compa rison subject who were matched on age, gender, and education. For some analyses, the two groups of patients were divided into subgroups acco rding to the degree of their cognitive impairment (mild, moderate, or severe) as determined by their scores on the Mini-Mental State examina tion. Results: Relative to the comparison subjects, both groups of pat ients showed cognitive deficits on each of the neuropsychological meas ures. The schizophrenic patients performed worse than the patients wit h Alzheimer's disease on rests of naming and constructional praxis but were less impaired on the test of delayed word recall. These differen ces were consistent across all levels of severity of globally measured cognitive impairment. Conclusions: Consistent with earlier findings f rom postmortem studies, these findings suggest that major differences exist in the neurobiologic mechanisms responsible for cognitive impair ment in schizophrenia and Alzheimer's disease. Effects directly attrib utable to social and environmental differences between these two group s of patients may also play a role.