BPD Researcher Searches for Puzzle's Missing Piece

The period since Gunderson first became fascinated with BPD has witnessed enormous expansion in the understanding of the heritability of the disorder and of its longitudinal course.

Among the more startling findings from CLPS and from the McLean Study of Adult Development (another longitudinal study of personality disorders, led by Gunderson's colleague at McLean, Mary Zanarini, Ed.D.), is that over time patients with BPD tend to get better symptomatically though they may not improve functionally. In an extension of the McLean Study of Adult Development that appeared online in AJP in Advance in April 2010, Zanarini and colleagues found that a substantial majority of patients with BPD experience remission of symptoms and that their remission tends to be stable over time compared with patients with other mental disorders (Psychiatric News, May 7, 2010).

But crucially, the study also found that only half of patients achieve good social and vocational functioning. So, for instance, while patients may cease cutting themselves or exhibiting other self-harming behaviors, some may remain unable to maintain close long-term relationships or a job.

"These patients experience significant remission in their psychopathology," Gunderson told Psychiatric News. "The remission in BPD occurs more slowly than for bipolar disorder or major depressive disorder, but about 85 percent of patients over a 10-year period will remit, which no one ever thought to be the case. And when they remit, they rarely relapse. But at the same time, many remain dysfunctional so that their public-health cost to society remains high, even though they may stop needing some treatment."

The finding has important implications for long-term outcome of treatment, since many of the psychotherapies for BPD are focused on specific domains of pathology but may not address long-term functioning.

Today, that insight is being advanced in a paper by Gunderson and colleagues in press with the Archives of General Psychiatry. The authors suggest that the separate domains of pathology that have been used diagnostically to identify BPD—emotional instability, impulsive aggression, interpersonal hypersensitivity—may be expressions of a common, as-yet-to-be-identified pathway, some X factor of dysregulation that is the core of "BPD-ness."

The study assessed the familial aggregation of BPD and its four major symptom "sectors" (defined as affective, interpersonal, behavioral, and cognitive) and tested whether the relationship of the familial and nonfamilial associations among the sectors can be accounted for by a "latent BPD construct" or unifying pathway.

What they found was substantial familial aggregation for BPD; they also found that all four sectors of psychopathology aggregated significantly in families. But the level of familial aggregation of BPD itself was higher than that of the individual sectors, suggesting that the relationship among the sectors must be explained by some common, unifying pathway.

The study suggests that efforts should be made to identify endophenotypes associated not only with individual sectors of BPD, but also with a more global tendency toward dysregulation that involves the several sectors of symptoms that together present as BPD.

Gunderson believes that the future of BPD research lies in unearthing this X factor, the common pathway for the behavioral endophenotypes that show up as the disorder.

"There is some kind of core to borderline pathology that is not about being either impulsive or emotional or interpersonally sensitive, something that isn't wholly captured by any of these characteristics," he told Psychiatric News. "This is important because our treatments that target one or another sector of behavior in BPD are not likely to get at the core."