Cognition in schizophrenia: Natural history, assessment, and clinical importance

Retrospective studies have demonstrated that schizophrenic patients often h ave poor premorbid cognitive function and social adjustment. Cross-sectiona l studies of the cognitive performance of schizophrenic patients aged 20 to 90 years indicate that there is a gradual decline in cognitive junction th roughout the adult life span. Comparison studies of Alzheimer's disease pat ients, geriatric schizophrenic patients, and normal subjects indicate that Alzheimer's disease patients have marked impairments in memory and executiv e function, with impairments in language and constructional ability develop ing later in the disease. In contrast, schizophrenic patients manifest move general cognitive impairment with less impairment in memory and move impai rment in visuospatial and language ability early in the course of dementia. Neuropathological findings indicate that the dementia associated with schi zophrenia is pathophysiologically distinct from that of Alzheimer's disease . Functional impairment in patients with schizophrenia is closely related t o cognitive deficit but not to positive and negative psychotic symptoms. Ba sed on these findings, assessment strategies for evaluation of antipsychoti c drug therapies are proposed to incorporate measures of psychosis, cogniti on, and function. [Neuropsychopharmacology 21:S203-S210, 1999] (C) 1999 Ame rican College of: Neuropsychopharmacology. Published by Elsevier Science In c.