Cognitive functioning in chronically hospitalized schizophrenic patients: age-related changes and age disorientation as a predictor of impairment

Although schizophrenic patients manifest cognitive impairments, there is considerable varaibility across patients in the severity of this impairment. Very chronic patients with a poor outcome, particularly geriatric patients, manifest the most severe impairments, which have often been characterized as resembling dementia. This study examined age-related changes in cognitive fonctioning in a sample of schizophrenic patients (n=393) ranging from 25 to 95 years of age, with a specific focus on identifying aspects of performance that were impaired in the youngest patients and preserved in the oldest patients. Age disorientation was examined in detail because it was previously found to predict global intellectual impairment in chronic patients. All 22 test items changed linearly over time (with age), with aspects of orientation, concentration, and delayed recall most impaired in young patients and naming and sentence repetition most preserved in the oldest patients. Age disoriented patients had more severe cognitive impairments at each age and the age-related changes in global impairment were more severe for these patients. The prevalence of age disorientation was consistent with previous reports and a one-year retest of the sample found that age disorientation was extremely stable over time within patients. The types of functions that are preserved in the oldest patients underscore previous findings of differences between geriatric schizophrenic patients and patients with degenerative diseases and the stability of age disorientation suggests that it is a trait of a subset of schizophrenic patients, those who appear to have the most severely declining course of illness.