Factors associated with borderline personality disorder in major depressive patients and their relationship to bipolarity.

Objective: To analyze the interface between borderline personality disorder (BPD) and bipolarity in depressed patients comorbid with BPD.

Methods: As part of National Multi-site Study of 493 consecutive DSM-IV major depressive patients evaluated in at least two semi-structured interviews 1 month apart, 19 (3.9%) had comorbid BPD (BPD+), whereas 474 (96.1%) did not manifest this comorbidity (BPD-).

Results: Compared to BPD (-), BPD (+) patients displayed higher rates of bipolar (BP) disorders and temperaments, an earlier age at onset with a family history of affective illness, more comorbidity, more stressors before the first episode which was more often depressive or mixed, as well as a greater number and severity of affective episodes.

Conclusions: The hypothesis which fitted at best our findings was to consider BPD as a contributory factor in the development of BP disorder, which could have favoured the progression from unipolar major depression to BP disorder. We could not however exclude that some features of BP disorder may have contributed to the development of BPD.