The convergence of neuropsychological testing and clinical ratings of cognitive impairment in patients with schizophrenia.

This study examined the relationship between clinical rating of cognitive symptoms and performance on neuropsychological tests in acute and chronic samples of patients with schizophrenia. Two separate studies examined patients who varied widely in their lifetime functional outcome, including 263 elderly poor-outcome inpatients and 20 acutely admitted patients. In the first study, six cognitive performance measures were collected, and in the second study, five different measures were collected. Correlations with different symptom models of cognitive and negative symptoms were examined. In both samples, cognitive symptoms were never more highly correlated with cognitive test performance than with negative symptoms. When cognitive and negative symptom ratings were combined, they never accounted for as much as half of the variance in performance on the cognitive tests in both samples. These data suggest that clinical assessment of symptoms is not a viable alternative to neuropsychological testing to obtain information about cognitive functioning in schizophrenia. These results may also be specific to the clinical rating scale used, the Positive and Negative Syndrome Scale (PANSS). Copyright 2001 by W.B. Saunders Company