Moderators of Treatment Outcome in Dialectical Behavior Therapy: The Role of Emotion Regulation and Impulsivity

Dialectical Behavior Therapy (DBT) has been shown to be effective in treating Borderline Personality Disorder (BPD) (Linehan, 1993). Less is known about how it works, or for whom. As emotion regulation, impulsivity, and experiential avoidance have been shown to be related to BPD symptoms, the current study sought to extend early evidence that these personality variables moderate treatment outcome. Participants included 30 clients engaged in DBT in a private practice in the Washington, DC metropolitan area. At the start of treatment, measures of difficulties in emotion regulation, impulsivity, and experiential avoidance were collected. Every two months, following each DBT group skills module, a brief self-rating of BPD symptoms was collected. Results indicated that suicidal ideation, impulsivity, anger, unstable identity, and paranoia all decreased over time in treatment. Emotion regulation deficits and impulsive tendencies moderated specific BPD symptoms. Those who initially indicated that they had a limited emotion regulation skills repertoire and difficulty thinking prior to action were helped the most in terms of their unstable identity and paranoia, when controlling for initial ratings of those symptoms. Difficulties with task persistence and difficulties engaging in goal-directed behavior while distressed were associated with the highest final ratings of suicidal ideation, unstable identity, and paranoia. Greater impulsive tendencies predicted greater difficulty with fear of abandonment at the final assessment. There was no evidence for the moderation of impulsive behaviors, dissociation, unstable relationships, unstable mood, or anger. Hypotheses regarding suicide attempts, suicidal threats, and self-injury were not tested, given the low base rates observed in this sample. Results were interpreted in light of extant knowledge of BPD symptoms as well as various outcome studies of DBT. The present study contributes to the understanding of the effectiveness of DBT in private, outpatient settings. Though the sample size is limited, such data are useful for clinicians in terms of determining who will be helped most in DBT, and what specific skills might best address specific symptoms.