Abstract
Borderline personality disorder (BPD) is characterized by maladaptive levels of neuroticism, agreeableness, and conscientiousness. The Unified Protocol (UP), a treatment for neuroticism, has previously demonstrated promising effects when applied to BPD; however, not all individuals with BPD respond, suggesting the UP may be incomplete for some BPD presentations. This secondary analysis explored the extent to which adapted versions of UP represent an efficacious treatment approach for BPD symptoms. Data from a subset of twelve participants with clinically-significant BPD features were included. We explored within-group changes in BPD symptoms and differences in within-person changes in BPD scores based on patients’ personality profiles. The UP resulted in improvements in BPD symptoms that were moderate in magnitude, Hedges’s g = 0.48, 95% CI [0.35, 0.62]. Individuals with personality profiles characterized by high neuroticism and low conscientiousness exhibited early gains in the UP but did not sustain them, whereas those with at least moderate levels of conscientiousness generally continued to improve across 12 weeks. Possible explanations and limitations were discussed.