Few Borderline-Personality Patients Eventually Develop Bipolar Disorder

Only a modest association appears to exist between borderline personality disorder (BPD) and bipolar disorder, seeming to refute the notion that BPD is a variant of bipolar.

A four-year longitudinal study at four institutions found that patients with BPD had a significantly higher co-occurrence of bipolar disorder than did patients with other personality disorders. But it was only modestly higher, and this co-occurrence did not appear to affect the subsequent course of BPD, according to a report in the July American Journal of Psychiatry.

“Our study shows that some borderlines go on to develop bipolar disorder, but it's a minority,” lead author John Gunderson, M.D., told Psychiatric News. “Bipolar illness occurs only modestly more frequently in BPD than in people with other types of personality disorder.”

He said the finding refutes the expectation, common among some clinicians, that many borderline patients will in time develop bipolar disorder, as if BPD were a form of bipolar disorder that hadn't yet fully matured. The study appears also to challenge more generally the notion that BPD is not a distinct clinical entity, but a variant of bipolar disorder.

Gunderson said some researchers and clinicians have proposed that bipolar illness is much more common in the general population than is commonly thought, occurring in a spectrum of symptoms including those that have been classified as BPD.

He added that the notion of BPD as a variant of bipolar illness has been seized upon by managed care because bipolar—in contrast to BPD and personality disorders generally—is perceived as a straightforward, biological disorder easily treatable with mood stabilizers. But Gunderson emphasized that mood stabilizers are liable to be “modestly helpful, but never dramatically helpful” for patients with BPD, and that psychotherapies, such as dialectical behavior therapy, appear to be much better.

“Our findings don't refute the idea that there is a spectrum of bipolar disorder in the population, but it does suggest that BPD is not a real close cousin,” Gunderson told Psychiatric News. “That's big news because modern psychiatry has been highly influenced by managed care and the biological perspective on illness. That has meant that anyone who has mood shifts is likely to be bipolar and treated with mood stabilizers, with an unrealistic expectation that it is going to be helpful.”

In the study, 192 patients with BPD and 433 patients with other personality disorders were followed for four years and reassessed at six months, one year, and every year after. All the patients were treatment-seeking individuals in a variety of treatment settings at the following institutions: Columbia University and the New York State Psychiatric Institute, Yale University and Yale Psychiatric Research, Brown University, and Texas A&M.

To examine the relationship of bipolar disorder to borderline personality disorder, researchers divided the borderline personality disorder group on the basis of presence (38 subjects) or absence (158 subjects) of lifetime co-occurring bipolar I or bipolar II disorder. As a comparison group, the patients with other personality disorders were likewise divided on the basis of presence (34 subjects) or absence (399 subjects) of lifetime co-occurring bipolar I or bipolar II disorder.

Comorbid bipolar I or bipolar II disorder occurred significantly more frequently in borderline personality disorder than in other personality disorders.

But the co-occurrence of bipolar and BPD did not appear to affect clinical course, global assessment of functioning, or number of hospitalizations. It also had no significant effect on use of SSRIs, other antidepressants, neuroleptics, or anticonvulsants over the four years.

Patients with borderline personality disorder without lifetime bipolar disorder had more new onsets of bipolar illness than other personality disorder patients, but the difference was not significant.

“Six new bipolar onsets followed significant stressful life events, two followed significant neurobiological changes, one followed both stressful life events and neurobiological change, and no precipitants were observed in three,” Gunderson and colleagues wrote in their report. “Clearly, the new onsets of bipolar disorder did not represent an evolution from borderline personality disorder psychopathology; rather, they most often followed stressful neurobiological or life changes. It remains to be determined whether a neurobiological disposition toward onsets of bipolar episodes was created due to the fact that our borderline personality disorder patients received far more medications than our patients with other personality disorders.”

In an interview with Psychiatric News, Gunderson said the clinical import of these findings is that clinicians should not jump to the conclusion that their patients who are impulsive and have mood changes have bipolar disorder. Instead they should “consider carefully” whether those changes are due to reactions to interpersonal events.

“Borderline patients are hypersensitive to any kind of rejection and other interpersonal slights,” Gunderson said. “Much of their psychopathology is organized around their fears that they will be hurt or abandoned. If you pay attention to that, you are likely to find that a lot of people who are impulsive and labile are borderline, and treatment recommendations should follow from that.

“Be wary of giving patients unrealistic hopes about mood stabilizers,” he continued. “It's not as if the two disorders can't ever coexist or that mood stabilizers are always bad. But it encourages optimism about recovery that is disillusioning. And when their medications multiply, then the over-medication becomes the problem. That's an unfortunate byproduct of this diagnostic inaccuracy and the temper of the times.”

The study was part of the Collaborative Longitudinal Personality Disorders Study funded by the National Institute of Mental Health.

“Descriptive and Longitudinal Observations on the Relationship of Borderline Personality Disorder and Bipolar Disorder” is posted at<http://ajp.psychiatryonline.org/cgi/content/full/163/7/1173>.▪