Structural validity, measurement invariance, reliability and diagnostic accuracy of the Italian version of the Yale Food Addiction Scale 2.0 in patients with severe obesity and the general population

Purpose: To examine the structural validity, measurement invariance, reliability, and some other psychometrical properties of the Italian version of the Yale Food Addiction Scale 2 (I-YFAS 2.0) in patients with severe obesity and the general population. Methods: 704 participants—400 inpatients with severe obesity and 304 participants enrolled from the general population—completed the I-YFAS 2.0 and questionnaires measuring eating disorder symptoms. A first confirmatory factor analysis (CFA) tested a hierarchical structure in which each item of the I-YFAS 2.0 loaded onto one of the twelve latent symptoms/criteria which loaded onto a general dimension of Food Addiction (FA). The second CFA tested a first-order structure in which symptoms/criteria of FA simply loaded onto a latent dimension. Measurement invariance (MI) between the group of inpatients with severe obesity and the sample from the general population was also tested. Finally, convergent validity, test–retest reliability, internal consistency, and prevalence analyses were performed. Results: CFAs confirmed the structure for the I-YFAS 2.0 for both the hierarchical structure and the first-order structure. Configural MI and strong MI were reached for hierarchical and the first-order structure, respectively. Internal consistencies were shown to be acceptable. Prevalence of FA was 24% in the group of inpatients with severe obesity and 3.6% in the sample from the general population. Conclusions: The I-YFAS 2.0 represents a valid and reliable questionnaire for the assessment of FA in both Italian adult inpatients with severe obesity and the general population, and is a psychometrically sound tool for clinical as well as research purposes. Level of evidence: Level V, descriptive study.