Validity and stability of performance-based estimates of premorbid educational functioning in older patients with schizophrenia

This paper presents the results of two studies of the validity of word-recognition reading as an indicator of premorbid functioning in schizophrenia. The first examined the stability over a 6-year follow-up period of word recognition reading compared to other aspects of cognitive functioning, including verbal learning and delayed recall, verbal fluency, constructional skills, and naming ability. The second study examined the relative predictive power of indicators of premorbid functioning as compared to current cognitive functioning for the prediction of current social and self-care skills. In the first study 218 patients with chronic schizophrenia participated. For the second study, 231 male veterans with schizophrenia were assessed for cognitive functioning, indicators of premorbid adjustment, and current functional status. Analyses of the differences between correlations indicated that word recognition reading ability was significantly more stable than other aspects of cognitive functioning over a six-year period during which decline in some other aspects of performance was found. In the second study, premorbid educational and social attainment, word recognition reading skill, and current cognitive functioning were all significantly related to current functional status, defined by correlations with ratings of current functional status. Path analyses indicated, however, that current cognitive functioning was the only significant predictor of current functional status when the intercorrelations of the variables were considered. In sum, Premorbid functioning estimated with word-recognition reading was stable over time (study 1) and correlated with both current cognitive and functional status (study 2). The results of these two studies suggest that word-recognition reading skills are useful screening instruments to estimate premorbid functioning even in deteriorated patients with schizophrenia.