Mindfulness in Borderline Personality Disorder: Decentering Mediates the Effectiveness.

Abstract

Mindfulness skills training is a core component of dialectical behavior therapy (DBT) that has proven to be an effective stand-alone treatment for the general symptoms commonly present in patients with borderline personality disorder (BPD). The aim of the present study was to compare the effectiveness of mindfulness-based DBT skills training (DBT-M) to interpersonal effectiveness-based DBT skills training (DBT-IE) in reducing BPD symptoms. We also evaluated the specific mechanism of action of these therapies through two proposed mediators: decentering and emotion dysregulation. A total of 102 participants diagnosed with BPD were included in the study. Multivariate repeated-measures ANOVAs were performed followed by a multiple mediation analysis. The analyses showed that DBT-M was more effective than DBT-IE in reducing BPD symptoms, although both interventions were effective in reducing emotion dysregulation. We identified a serial mediation model in which DBT-M reduced BPD symptoms by increasing decentering ability, which in turn reduced emotion dysregulation. This mediation effect showed that changes in decentering preceded improvements in emotion dysregulation. These findings underscore the key role of decentering as a primary mechanism of action in DBT-M, suggesting that this skill is a main component for BPD treatment.