The role of mindfulness and emotion regulation in dialectical behavioural therapy for borderline personality disorder

Despite substantial research demonstrating its effectiveness in the treatment of borderline personality disorder (BPD), few studies have investigated mechanisms of change for dialectical behavior therapy (DBT). Improvements in mindfulness and emotion regulation have been highlighted as potential mechanisms. This study examined the time course of, and associations between, mindfulness, emotion regulation and BPD symptoms during DBT. Participants were 240 self-harming adults with BPD who were randomly assigned to receive 6- or 12-months of DBT. Results from changepoint analysis indicated that changes in emotion regulation preceded changes in mindfulness. Contrary to hypotheses, cross-lagged analyses did not indicate mediational effects of mindfulness or emotion regulation on the association of either variable with change in BPD symptoms. Supplemental analyses, however, suggested that changes in emotion regulation mediated the inverse association of changes in mindfulness with changes in BPD symptoms. Findings highlight patterns of change in proposed mechanisms of change in DBT.