Beyond standard therapy: clinical transdiagnostic study evaluating mindfulness-based training as an adjunct to CBT for dissociation.

Background: Mindfulness-based interventions show promise for trauma-related conditions, yet controlled trials examining their efficacy for dissociative symptoms remain scarce. This feasibility study evaluated whether Mindfulness-Based Training (MBT), when added to cognitive-behavioral therapy (CBT), reduces dissociative symptoms more effectively than CBT combined with guided physical exercise. Methods: A controlled pseudo-randomized design was employed with 104 participants assigned to either MBT plus CBT (intervention) or CBT plus physical exercise (active control). Dissociative symptoms were assessed using the Dissociative Experiences Scale (DES-II) at baseline, post-treatment, and 12-week follow-up. Robust mixed-effects linear regression models examined treatment effects and potential moderators including sex and personality domains (Personality Inventory for DSM-5 - PID-5). Results: MBT did not outperform the active control condition. Both groups showed modest improvements in dissociation scores. Exploratory analyses identified sex and antagonism as potential moderators of treatment response. Conclusions: MBT as an adjunct to CBT did not demonstrate superior efficacy compared to CBT plus guided physical exercise for reducing dissociative symptoms. Both groups improved modestly during treatment. Moderation findings regarding sex and personality traits are exploratory, not pre-registered, and require independent replication. The study supports the feasibility of integrating low-intensity MBT into clinical settings rather than establishing its efficacy.