Turkish Version of the New Instrument for Orthorexia Nervosa-Test of Orthorexia Nervosa (TON-17): A Validity and Reliability Study.

This study aimed to adapt the Test of Orthorexia Nervosa- (TON-17) into Turkish and verify its validity and reliability. The study included 539 adults with a mean age of 30.2 ± 12.26 years. A reliability analysis was performed, along with a confirmatory factor analysis to test its construct validity. The time-invariance of the scale was examined by test-retest analysis, and its convergent validity was evaluated by a correlation analysis conducted to test the relationships between the scale and Eating Attitudes Test-26 and Obsessive Beliefs Questionnaire-9. Analyses were conducted using SPSS Version 28 and the AMOS-24 software. The Cronbach's α internal consistency coefficient of the total scale was found to be 0.82, suggesting a strong internal consistency. The Cronbach's α values of its factors were 0.68 for the "control of food quality", 0.64 for the "fixation on health and a healthy diet", and 0.73 for the "disorder symptoms". In addition, the test-retest reliability was found to be 0.87 for the total scale, suggesting excellent reliability. Most of the fit indices (CMIN/df, RMSEA, AGFI, NFI, and TLI) of the scale were acceptable, and the GFI indicated a good model fit. This study shows that the Turkish version of TON-17, which is a new tool with a three-factor structure to evaluate orthorexia, is a valid and reliable scale.