Schizophrenia Bulletin Advance Access published online on July 30, 2008
Schizophrenia Bulletin, doi:10.1093/schbul/sbn095
Cognitive Performance and Functional Competence as Predictors of Community Independence in Schizophrenia
2 Department of Psychology, York University, 4700 Keele Street, Toronto, ON M3J 1P3
3 Cleghorn Early Intervention in Psychosis Program, St Joseph's Healthcare Hamilton, Hamilton, ON
1 To whom correspondence should be addressed; tel: 1-416-736-2100, ext 66205, fax: 1-416-736-5814, e-mail: walterh{at}yorku.ca.
Measures of functional competence have been introduced to supplement standard cognitive and neuropsychological evaluations in schizophrenia research and practice. Functional competence comprises skills and abilities that are more relevant to daily life and community adjustment. However, it is unclear whether relevance translates into significantly enhanced prediction of real-world outcomes. The aim of this study was to assess the specific contribution of functional competence in predicting a key aspect of real-world outcome in schizophrenia: community independence. Demographic, clinical, cognitive, and functional competence data were obtained from 127 patients with schizophrenia or schizoaffective disorder and used to predict community independence concurrently and longitudinally after 10 months. Hierarchical regression analyses indicated that demographic, clinical, and cognitive predictors accounted jointly for 35%–38% of the variance in community independence across assessment points. Functional competence data failed to add significantly to this validity. Considered separately from demographic and clinical predictors, cognitive and functional competence data accounted for significant amounts of outcome variance. However, the addition of functional competence to standard cognitive test data yielded a significant increase in validity only for concurrent and not for longitudinal prediction of community independence. The specific real-world validity of functional competence is modest, yielding information that is largely redundant with standard cognitive performance.
Keywords: cognition / functional competence / real-world outcome