Validity of the premorbid adjustment scale

Background. The aim of the current study was to test the predictive and concurrent validity of the Premorbid Adjustment Scale (PAS) by comparing it with another similar but more elaborate retrospective measure and with data collected during late adolescence. Methods: We compared PAS late adolescence scores (age 16-18 years) of 91 males with schizophrenia or schizoaffective disorder with data on behavior collected in adolescence, before the first psychotic episode as part of standardized Draft Board screening, and with the same measure readministered during adulthood and modified to collect the same data again retrospectively. Results: The correlation of the PAS social withdrawal and social relations items with the social behavior scale of the Draft Board were .76 and .80, respectively, for the concurrent ratings and .52 and .53, respectively, for the data collected at age 17 years. The correlation of the PAS school achievements and school adjustment items with the functioning in structured environments scale of the Draft Board were .71 and .72, respectively, for the concurrent ratings and .43 and .47, respectively, for the data collected at age 17 years. Conclusions: Our results support the predictive and concurrent validity of the PAS and the validity of self-reported data on premorbid functioning in persons with schizophrenia.