Editor's Note: Relationship of BPD to Bipolar Disorder

Norman Sussman, MD, DFAPA

Editor, Primary Psychiatry and Psychiatry Weekly, Professor of Psychiatry, New York University School of Medicine

Borderline personality disorder (BPD) is a disabling condition characterized by a history of tumultuous interpersonal relationships and repeated suicide gestures and self-injurious behavior, such as wrist cutting. Differentiating BPD from bipolar disorder may be difficult. Both diagnoses are associated with mood instability, impulsivity, and interpersonal difficulties. Some authors even argue that BPD represents a “soft form” of bipolar disorder. The question is of more than academic interest, since the treatment approach may differ depending on the diagnosis. For example, the American Psychiatric Association practice guidelines state that psychotherapy is the primary treatment modality for BPD, with medication used as an adjunct to target specific symptoms. In the case of bipolar disorder, pharmacotherapy is considered the main intervention.

To determine if BPD is in fact a variant of bipolar disorder, a just-published study looked at rates of co-occurrence in both disorders, the effects of co-occurrence on a longitudinal course, and whether the presence of either disorder confers the risk for new onsets of the other. The investigators found that the rate of co-occurring bipolar disorder in these patients was 19%. This rate was higher than that among patients with other personality disorders. That rate was 8%. Among the patients who did not have bipolar disorder at study outset, 8% of the BPD patients developed bipolar disorder over the next four years. This rate was only 3% among the patients with other personality disorders.

This finding of a “modest association” between BPD and bipolar disorder has therapeutic implications. Many BPD patients misdiagnosed as having bipolar disorder may be managed with medication alone. If correctly diagnosed with BPD, psychosocial interventions, such as dialectical behavior therapy, should be considered.

Other positive findings of the study were that co-occurrence of BPD bipolar disorder did not appear to worsen the course of BPD. Remission rates, approximately 65% over a four-year period, were the same among BPD patients with and without bipolar disorder.

Disclosure: Dr. Sussman reports no affiliations with or financial interests in any organization that may pose a conflict of interest.

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