Validation of orthorexia nervosa scales in late adolescent women: ORTO-R Scale, Teruel Orthorexia Scale, and Düsseldorf Orthorexie Scale

This study evaluated the psychometric properties of three orthorexia measures, ORTO-R, Teruel Orthorexia Scale (TOS), and Düsseldorf Orthorexia Scale (DOS), in 1337 Croatian women aged 18 to 21. Participants also completed eating disorder measures (EAT-26, DEAS-S). Confirmatory factor analysis tested structural validity. The TOS (two-factor: χ²/ df = 9.40, CFI = 0.951, TLI = 0.943, RMSEA = 0.079, SRMR = 0.070) and DOS (single-factor: χ²/ df = 10.68, CFI = 0.980, TLI = 0.972, RMSEA = 0.085, SRMR = 0.037) showed good fit and strong reliability (TOS ω = 0.85/0.89; DOS ω = 0.86), with associations with eating disorder symptoms, supporting convergent validity. In contrast, the ORTO-R showed weaker reliability (ω = 0.60) and, despite modifications improving some indices (CFI = 0.953, TLI = 0.912, SRMR = 0.044), retained high RMSEA (0.116), indicating limitations. Overall, the TOS and DOS appear reliable tools for assessing orthorexia, whereas the ORTO-R demonstrates psychometric weaknesses.