Examining the Construct Validity of Borderline Personality Traits Using Familial Aggregation and Other External Validators.

Numerous studies have questioned the reliability and validity of borderline personality disorder's (BPD) categorical conceptualization. DSM-5 Section III's alternative trait-based model of BPD may better capture borderline pathology, but aspects of its validity should be further established. Thus, the authors examined whether a latent BPD factor derived from Section III traits exhibits (1) familial aggregation among siblings and (2) association with constructs related to borderline pathology. The authors also tested whether gender moderated associations. A total of 498 community-recruited adults completed the Personality Inventory for DSM-5, a behavioral assessment of risk-taking, and reported their history of childhood maltreatment, substance use, nonsuicidal self-injury, and suicidal ideation. Familial aggregation was assessed among 232 sibling pairs. Siblings' BPD scores were significantly correlated and most external validators were significantly associated with BPD, with the exception of risk-taking. Results did not vary by gender. Findings further support the construct validity of Section III's BPD trait profile.