Target validation in dialectical behavior therapy skills group: Emotion regulation, mindfulness, and distress tolerance as mediators of outcome

Abstract Objective There is increasing interest in identifying mediators in dialectical behavior therapy (DBT), particularly within the broader DBT framework and the specific skills taught in group-based interventions. This study examined whether three core DBT skills—emotion regulation, mindfulness, and distress tolerance— mediate the relationship between group therapy participation and borderline personality disorder (BPD) symptoms in university students. It was hypothesized that improvements in these skills would mediate treatment outcomes, reflecting their role in driving therapeutic change.

Methods: Fifty-four participants were randomly assigned to a 12-week DBT or positive psychotherapy (PPT) group and completed baseline and posttreatment assessments of treatment-specific factors. Data were analyzed using mediation models to examine the relationship between treatment group and BPD symptoms, with emotion regulation, distress tolerance, and mindfulness as mediators.

Results: Impulse control and access to emotion regulation strategies were significant mediators of the relationship between treatment group and BPD symptoms, with stronger effects observed in the DBT group compared to the PPT group. Additionally, acting with awareness, a mindfulness skill, was found to mediate treatment outcomes, whereas other mindfulness aspects and distress tolerance were not significant mediators.

Conclusion: Results highlight the importance of targeting impulse control, emotion regulation, and acting with awareness in the treatment of BPD symptoms.