Psychometric characteristics of the Persian version of the Dissociative Experiences Scale (DES-II) in patients with multiple sclerosis (PWMS)

People with multiple sclerosis (PWMS) may experience psychological challenges, including dissociative symptoms. Accurate assessment of these symptoms requires psychometrically sound instruments. This study aimed to evaluate the reliability and validity of the Persian version of the DES-II for use in PWMS in Iran. In this cross-sectional, registry-based study, 257 PWMS were recruited from the nationwide MS Registry of Iran (NMSRI). Data were collected over a four-month period in 2023. The back-translated Persian version of the DES-II was administered. Reliability was assessed using Cronbach’s alpha, Guttman’s lambda, and composite reliability. Validity was evaluated through confirmatory factor analysis (CFA), average variance extracted (AVE), maximum shared variance (MSV), and average shared variance (ASV), using SPSS 24 and AMOS. CFA supported the three-factor structure, with most factor loadings exceeding 0.50. Model fit indices indicated an acceptable fit. Internal consistency was strong across factors (all reliability coefficients > 0.70). However, AVE, MSV, and ASV values suggested limitations in convergent and discriminant validity within this sample. The Persian version of the DES-II supported satisfactory internal consistency and acceptable factorial validity in PWMS. Nevertheless, concerns regarding certain aspects of construct validity, along with non-random sampling and gender imbalance, warrant cautious interpretation and further validation in diverse samples.