Psychometric properties of the Swedish version of the Reynolds Adolescent Depression Scale second edition (RADS-2) in a clinical sample

Objective: Observed and predicted increases in the global burden of disease caused by major depressive disorder (MDD) highlight the need for psychometrically robust multi-dimensional measures to use for clinical and research purposes. Reynolds Adolescent Depression Scale second edition (RADS-2) is an internationally well-validated scale measuring different dimensions of adolescent depression. The Swedish version has previously only been evaluated in a normative sample. Methods: We collected data from patients in child and adolescent psychiatry and primary care and performed: (1) Confirmatory factor analysis (CFA) to evaluate the established four-factor structure, (2) Analyses of reliability and measurement invariance, (3) Analyses of convergent and discriminant validity using the Montgomery-Asberg Depression Rating Scale, the depression subscales of the Beck Youth Inventories and the Revised Child Anxiety and Depression Scale, as well as the Patient Reported Outcome Measurements Information System, peer-relationships and physical activity item banks. Results: Recruited participants (n = 536, 129 male and 407 female, mean age 16.45 years, SD = 2.47, range 12 - 22 years) had a variety of psychiatric diagnoses. We found support for the four-factor structure and acceptable to good reliability for the subscale and total scores. Convergent and discriminant validity were good. Measurement invariance was demonstrated for age, sex, and between the present sample and a previously published normative sample. The RADS-2-scores were significantly higher in the present sample than in the normative sample. In this clinical study, the Swedish RADS-2 demonstrated good validity and acceptable to good reliability. Our findings support the use of RADS-2 in Swedish clinical and research contexts.