Normative and maladaptive personality traits in borderline personality disorder: a comparative and hierarchical analysis of HEXACO and PID-5

Dimensional models of personality pathology invite the question of how normative and maladaptive trait systems jointly characterize borderline personality disorder (BPD). This study examined how the HEXACO model of personality and the DSM-5 Alternative Model of Personality Disorders trait system, operationalized with the Personality Inventory for DSM–5, differentiate individuals with BPD from mentally healthy control (HC) individuals, both separately and jointly. Data from two assessment waves of a large clinical research program were combined into a final sample of 575 participants (233 with BPD, 342 HC). A joint item-level PCA was conducted to examine seven- and eleven-component solutions, and a Bass-Ackwards analysis was conducted to examine the joint hierarchical structure of HEXACO and PID-5 items. Both instruments were administered as self-reports. Compared with HC, individuals with BPD showed lower HEXACO Extraversion, Agreeableness, and Conscientiousness, and higher Emotionality, as well as higher scores on all PID-5 domains, particularly Negative Affectivity and Disinhibition. In the combined domain model, low Extraversion and high PID-5 Negative Affectivity, Disinhibition, and Psychoticism uniquely predicted BPD status. At the facet level, low Social Self-Esteem (HEXACO) and high Emotional Lability (PID-5) were especially discriminative. Joint item analyses yielded a seven-component solution in which six components corresponded closely to the six HEXACO factors and a dominant seventh component represented broad maladaptivity, with PID-5 items loading positively and HEXACO items largely loading inversely. Group differences were almost entirely confined to this broad component. These findings suggest that BPD is characterized by both a broad maladaptivity dimension and a more specific trait profile involving affective instability, interpersonal insecurity, irritability, and reduced behavioral control. The findings support integrating normative and maladaptive trait models in the dimensional description of BPD, while indicating that the dominant joint dimension cannot be interpreted unambiguously as a substantive general factor of personality pathology.