The unique contribution of acceptance without judgment in predicting nonsuicidal self-injury after 20-weeks of dialectical behaviour therapy group skills training

Abstract

The current research tested whether four dimensions of mindfulness - acceptance without judgment, observing, describing and acting with awareness - predicted frequency of nonsuicidal self-injury (NSSI) and mediate the relationship with NSSI outcomes during 20-weeks of Dialectical Behaviour Therapy (DBT) skills training for borderline personality disorder (BPD). Eighty-four self-harming individuals with BPD were randomized to either DBT skills training or to a waitlist control group. A series of regressions revealed no relationship between dimensions of mindfulness and NSSI at baseline. There was a significant effect of DBT skills training on NSSI. As well, mediation analysis indicated that acceptance without judgment, specifically, mediated the relation between DBT skills training and change in frequency of NSSI.

Trial registration: ClinicalTrials.gov NCT01193205.

Keywords: Dialectical behaviour therapy; Mechanisms; Mindfulness; Nonsuicidal self-injury.