Although a considerable amount of neuropsychological research has been conducted in schizophrenia, relatively little is known about the cognitive functions associated with schizophrenia and other psychoses in later life. During the initial funding period of the CRC, we began to characterize the neuropsychological patterns of individuals with psychosis in late life and to differentiate the cognitive profiles of these patients from those of their younger counterparts and of patients with other diseases associated with aging. Our findings thus far have suggested that the level and pattern of neuropsychological performance in older patients with schizophrenia are generally quite similar in both early-onset and late- onset groups (and very different from patients with early Alzheimer's disease). Nevertheless, some qualitative differences do exist among cohorts of patients with schizophrenia: (a) performances on semantic memory and episodic memory tasks vary with age-of-onset; (b) the pattern of learning and memory impairments in schizophrenia is heterogeneous among schizophrenia patients (viz., 50% have a """"""""subcortical"""""""" profile, 15% have a """"""""cortical"""""""" profile, and 35% have """"""""normal"""""""" learning and memory); (c) the overall level of neuropsychological impairment in older patients with schizophrenia is worse in patients with tardive dyskinesia; and (d) the specific cognitive abilities of attention and learning are more impaired in patients with tardive dyskinesia. In addition, we have found that the level of neuropsychological impairment in patients with late life psychoses remains stable over a 3-year period, and that psychosis patients with a diagnosis of unipolar depression are neuropsychologically more similar to patients with a diagnosis of schizophrenia than to patients with unipolar depression who are not psychotic. During the CRC renewal period, the Neuropsychology Core proposes to address several additional aspects of the neuropsychology of schizophrenia by pursuing the following scientific objectives: (a) further elucidating the specific nature of memory impairments across the full spectrum of late life psychosis, and relating memory findings to clinical characteristics, psychophysiological performances, and neuroimaging measures of frontostriatal and temporolimbic volumes; (b) increasing the generalizability of our findings regarding the current illness severity, by adding schizophrenia patients at the extremes of this dimension (i.e., institutionalized and remitted patients); (c) examining the effects of neuropsychological impairment on functional outcome of schizophrenic disorders in older age groups; and (d) further establishing the reliability and stability of neuropsychological deficits over longer time periods, and their relative independence from changes in symptom status and treatment effects.
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