Abstract
Background/Objectives: Dialectical Behaviour Therapy (DBT) has emerged as a promising intervention for Eating Disorders (Eds), especially Binge Eating Disorder (BED), which is often characterized by severe emotion dysregulation. The aims of this study were to evaluate the longitudinal course of BED symptomatology following a group-based DBT intervention focused on two specific modules, Emotion Regulation and Distress Tolerance, and to examine the mediating role of emotion dysregulation and alexithymia in symptom improvement. Methods: This non-randomized longitudinal clinical study involved 170 patients with BED who received a 16-week DBT group treatment including modules targeting emotion regulation and distress tolerance. Self-report questionnaires were administered at baseline (T0) and at the end of treatment (T1). Linear mixed models were used to analyze the longitudinal trend, and a mediation analysis was conducted to examine whether changes in emotion dysregulation and alexithymia mediated symptom improvement. Results: Longitudinal analyses showed a significant reduction in BED symptoms at the end of treatment as well as in the levels of emotion dysregulation and alexithymia. Mediation analyses revealed that both emotion dysregulation (indirect effect: -0.68 [-1.20; -0.31]) and alexithymia (indirect effect: -0.59 [-1.33; -0.20]) significantly mediated the improvement in BED symptoms over time. Conclusions: These findings support the application of focused DBT group interventions targeting emotion regulation and distress tolerance in reducing BED symptomatology. Emotion dysregulation and alexithymia were identified as mediators of longitudinal clinical improvement, highlighting the importance of modular and precision-based approaches in the treatment of BED.