Context The familiality of borderline personality disorder (BPD) and its sectors of psychopathology are incompletely understood.
Objectives To assess the familial aggregation of BPD and its 4 major sectors (affective, interpersonal, behavioral, and cognitive) and test whether the relationship of the familial and nonfamilial associations among these sectors can be accounted for by a latent BPD construct.
Design Family study, with direct interviews of probands and relatives.
Setting A psychiatric hospital (McLean Hospital) and the Boston-area community.
Participants A total of 368 probands (132 with BPD, 134 without BPD, and 102 with major depressive disorder) and 885 siblings and parents of probands.
Main Assessments The Diagnostic Interview for DSM-IV Personality Disorders and the Revised Diagnostic Interview for Borderlines (DIB-R) were used to assess borderline psychopathology, and the Structured Clinical Interview for DSM-IV was used to assess major depressive disorder.
Results Borderline personality disorder meeting both DSM-IV and DIB-R criteria showed substantial familial aggregation for BPD in individuals with a family member with BPD vs those without a family member with BPD, using proband-relative pairs (risk ratio, 2.9; 95% confidence interval, 1.5-5.5) as well as using all pairs of family members (3.9; 1.7-9.0). All 4 sectors of BPD psychopathology aggregated significantly in families, using both DSM-IV and DIB-R definitions (correlation of traits among all pairs of family members ranged from 0.07 to 0.27), with the affective and interpersonal sectors showing the highest levels; however, the level of familial aggregation of BPD was higher than that of the individual sectors. The relationship among the sectors was best explained by a common pathway model in which the sectors represent manifestations of a latent BPD construct.
Conclusions Familial factors contribute to BPD and its sectors of psychopathology. Borderline personality disorder may arise from a unitary liability that finds expression in its sectors of psychopathology.