Discriminative Performance of the Italian Multiscale Dissociation Inventory: Total Score Cutoff and Subscale Contributions

Multidimensional measures of dissociation enable detailed characterization of dissociative phenomena, yet their clinical use is limited by the lack of validated cutoff scores. The Italian version of the Multiscale Dissociation Inventory (MDI-ITA) has demonstrated solid psychometric properties, but its diagnostic accuracy in identifying clinically significant dissociation has not been investigated. This study reports a secondary analysis of data from the Italian validation of the MDI-ITA, including 439 adults from the general population. Clinically significant dissociation was operationalized using the Dissociative Experiences Scale-II cutoff score (≥30). Receiver Operating Characteristic (ROC) analyses were conducted to evaluate the discriminative accuracy of the MDI-ITA total score and its five subscales (Disengagement [DIS]; Depersonalization-Derealization [DP/DR]; Emotional Constriction [EC]; Memory Disturbances [MD]; Identity Dissociation [ID]). The cutoff for the total score was identified using the Youden Index. The MDI-ITA total score showed good discriminative accuracy (AUC = 0.885). The optimal cutoff value of 52 yielded a sensitivity of 70.6% and a specificity of 90.9%, favoring exclusion of non-cases. Subscale analyses revealed heterogeneous but overall fair discriminative performance, with DP/DR and DIS demonstrating the highest accuracy. Thresholds derived for subscales were interpreted dimensionally and not as independent diagnostic cutoffs. The findings support the use of the MDI-ITA total score as a screening index for potentially clinically significant dissociation. While the multidimensional structure of the MDI-ITA remains essential for dimensional characterization, the availability of the total-score cutoff enhances its applicability in assessment and research contexts requiring both classification and dissociation profiling.