Associations between changes in normal personality traits and borderline personality disorder symptoms over 16 years

There has been significant movement toward conceptualizing borderline personality disorder (BPD) with normal personality traits. However, 1 critical assumption underlying this transition, that longitudinal trajectories of BPD symptoms and normal traits track together, has not been tested. We evaluated the prospective longitudinal associations of changes in Five-Factor Model traits and BPD symptoms over the course of 16 years using parallel process latent growth curve models in 362 patients with BPD (n = 290) or other PDs (n = 72). Moderate to strong cross-sectional and longitudinal associations were observed between BPD symptoms and Neuroticism, Extraversion, Agreeableness, and Conscientiousness. This study is the first to demonstrate a longitudinal link between changes in BPD symptoms and changes in traits over an extended interval in a clinical sample. These findings imply that changes in BPD symptoms occur in concert with changes in normal traits, and support the proposed transition to conceptualizing BPD, at least in part, with trait dimensions.