The Role of Executive Functioning in the Treatment of Borderline Personality Disorder

Thesis (Ph.D.)--University of Washington, 2014Borderline Personality Disorder (BPD) is characterized as a problem of emotion regulation and impulsivity that becomes increasingly problematic over time due to deficits in problem solving. Problem solving incorporates the executive functions, such as planning, organization, cognitive flexibility, decision making, and inhibitory control. Despite their assumed importance in psychotherapy, the executive functions are seldom examined in treatment research. The present study examines three forms of executive functioning (figural fluency, verbal fluency, and inhibition) for their role in the treatment of BPD. This study is based on data previously collected in a one year randomized control trial (Linehan et al., 2006) which compared dialectical behavior therapy (DBT) to a community treatment by experts (CTBE) for its effectiveness in treating BPD. Participants included 101 women with recent suicidal and self-injurious behaviors who met DSM-IV criteria for a diagnosis of BPD. First, this study tested whether any of the three aforementioned forms of executive functioning (figural fluency, verbal fluency, and inhibition) served as predictors of three important post-treatment therapy outcomes: reductions in depression, suicide attempts (SA), and non-suicidal self injury (NSSI). This study also tested a second hypothesis as to whether these three forms of executive functioning moderate the relationship between the treatment condition (DBT vs CTBE) and the outcomes (depression, SA, NSSI). In a third hypothesis, it was predicted that treatment condition (DBT vs CTBE) could enhance executive functioning. The results for all three of these hypotheses were primarily null findings, with some minor exceptions in the second hypothesis. These exceptions were that while none of the executive functions (figural fluency, verbal fluency, and inhibition) demonstrated consistent moderation across all the outcome measures, they did each show evidence for moderating the treatment on at least one outcome each (depression, SA, or NSSI). Limitations of the study are discussed, particularly emphasizing the possibility for increased Type I and II errors from running many analyses on a moderately sized sample. Though the hypotheses were largely unsupported, these findings remain encouraging as they may suggest that both of these treatments positively benefit therapy clients regardless of their pre-existing executive functioning abilities