Two operationalizations of a single construct: Overlap between borderline personality disorder and the level of personality functioning.

Scholarly debate continues regarding whether borderline personality disorder (BPD) represents a distinct categorical disorder or primarily reflects elevated levels of personality functioning (LPFs) as conceptualized in the Diagnostic and Statistical Manual of Mental Disorders, fifth ed., Alternative Model of Personality Disorders. The present study examined the overlap between measures of LPF and BPD by analyzing archival data from 289 adults receiving community-based mental health treatment. Participants completed both clinician-rated and self-report measures assessing BPD symptoms, LPF, and relevant psychopathology and personality constructs. Results indicated substantial overlap between measures of BPD and LPF, with confirmatory factor analyses and bifactor modeling supporting a dominant general factor that accounted for most shared variance between the 2 constructs. Concurrently, BPD retained modest yet consistent unique variance, primarily associated with externalizing domains. Together, these findings indicate that BPD largely reflects LPF with some stylistic features remaining unique that are likely artifacts of the behavioral focus of BPD in the Diagnostic and Statistical Manual of Mental Disorders, fifth ed. This observation suggests that resources currently directed toward BPD-specific frameworks may be more effectively invested in dimensional models targeting general personality impairment, with benefits extending across broader personality pathology. (PsycInfo Database Record (c) 2026 APA, all rights reserved).