Factor structure models of the SCL-90-R: Replicability across community samples of adolescents.

Derogatis' Symptom Checklist-90-Revised (SCL-90-R) is one of the most widely used measures of psychological distress in both the clinical and the research settings, although its factor structure is still debated. In this study, the factor structure of the SCL-90-R has been investigated in two independent samples of Italian adolescents. Two samples of 817 (urban sample) and 507 (rural sample) adolescents attending high schools were involved. Confirmatory factorial analysis (CFA) was used alongside hierarchical nested, progressively constrained models to assess configural, metric and scalar invariance of the best models fitted by CFA. The standard nine-factor structure of the SCL-90-R resulted reproducible and invariant between the two samples, in both its correlated and hierarchical second-order implementations. Estimated reliability of the nine scales of the SCL-90-R was optimal. This study also confirmed the reproducibility of the bifactor models of the SCL-90-R with nine orthogonally independent factors and with nine correlated primary factors, which have been tested in some recent studies. Overall, the SCL-90-R measures both common and unique features of psychological distress in community samples. The measurement invariance across different levels of psychological distress in the factor structure of the SCL-90-R is an issue deserving further testing and investigation.