Looking Below the Threshold in Borderline Personality

A new study on borderline personality reveals its two subthreshold dimensions.

Posted Apr 11, 2020

Even without a diagnosis, people who have symptoms of borderline personality disorder (BPD) can experience challenges in their daily lives. To receive a diagnosis of this disorder, people need to exhibit a minimum number of symptoms out of a range of possibilities that include inability to regulate emotions, impulsivity, unstable relationships, and disturbances in sense of self. However, consider what it’s like to have just one or two of those symptoms.

Perhaps you have a close friend or relative who shows that inability to regulate emotions, also called emotion dysregulation. This individual becomes enraged for what you would regard as a small annoyance, such as an unexpected extra charge on a monthly bill. Not only does this loss of emotional control create undue stress for everyone involved, but it fails to solve the problem. If this were to happen at the workplace, a supervisor would surely issue a stern reprimand. Repeated occurrences would undoubtedly result in the employee being fired.

According to Pennsylvania State University’s Benjamin Johnson and Kenneth Levy (2020), people with just one BPD symptom show “significantly worse psychosocial functioning,” including increased suicidality, rates of hospitalization, and problems at work. Notably, people with “subthreshold ‘remitted’ BPD” experience “continued functional impact." These findings from the literature suggest that it’s important to look at BPD not only as a collection of a minimum number of symptoms, but also in terms of its individual components. As the authors note, the DSM-5, the current diagnostic manual, contains criteria that are “largely arbitrary” and do not “carve nature at its joints.” Holding fast to all BPD criteria also means that people with these symptoms won’t get the help they need in order to manage in their daily lives if they are just below that diagnostic threshold.

Consistent with attempts by researchers to regard personality disorders from a dimensional rather than from an all-or-nothing categorical approach, Johnson and Levy sought to dig into what’s called the “latent,” or underlying structure of BPD. The Penn State researchers believed from prior work that this approach would reveal two underlying dimensions or subtypes: impulsive and identity disturbed. Along the impulsive dimension, you would find that individual who blows up at the slightest perturbation, because the inability to control emotions would be part of its inherent quality. The identity disturbed dimension, which the authors also call “empty and chaotic,” would incorporate the lack of clarity that people with BPD have about their basic sense of self. This dimensional approach would mean, furthermore, changing the way symptoms are counted, adding an underlying severity indicator to allow a graduated scale from healthy to personality disordered.

This two-pronged framework could apply well, according to Johnson and Levy, to people who don’t have a BPD diagnosis but who may fall somewhere along a scale of lower to higher severity. Following this logic, the authors took advantage of the large numbers of participants they could study from years of previously collected data provided by samples of college students. Over the 10-year period from 2006 to 2016, slightly over 20,000 students (67% female) enrolled in the university’s subject pool, and most of these provided data for the present research. All completed a standard BPD questionnaire along with well-validated personality trait measures. Participants were also asked to complete self-report tests on related measures including self-concept clarity or identity “diffusion,” attachment style, reckless behavior and suicidality, depression-anxiety, and emotional reactivity.

After subjecting this vast amount of data to statistical tests, the authors identified three classes or groupings in their sample. The first group had no symptoms at all, which is what you would expect in a nonclinical sample. The second group showed high levels of emotion dysregulation (primarily anger) as well as endorsement of high-risk behaviors. Finally, the third group were high on lack of self-concept clarity, or emptiness, as well as general feelings of emotional distress. Looking at the severity dimension, it was this third group (called “Empty” for short) who were most likely to rate along the high end of the scale and would therefore be most likely to meet the DSM’s diagnostic criteria for BPD.

In examining these combined results, Johnson and Levy suggested that another way to view the two main subtypes of BPD is along a familiar distinction used in clinical psychology, namely “internalizing” vs. “externalizing” symptoms. Those who internalize, or who are empty and distressed, tend to turn their emotions inward, allowing their feelings of anger, depression, and anxiety to rage against and within themselves. Not only can do they experience frequent negative emotions, but their insecurity in terms of their sense of self will also make it hard for them to rely on others, leading to a certain degree of chaos in their close relationships. When you’re feeling confident and secure, you know that you can rely on your partners no matter what, but when you’re plagued by self-doubts, you’ll find it difficult to believe that other people can truly love you for who you are.

People who externalize, that second subtype, lash out at others when their emotions become out of control and can therefore also put themselves in harm’s way by acting out impulsively. Returning to the example of your relative or coworker who shows this pattern of lack of emotion control, it’s this outwardly-turning set of qualities that can create the most practical, real-life consequences. These individuals, furthermore, may put themselves at risk in situations that can result in physical injury in such situations as getting into fights, driving erratically, or punching out a wall.

As you can see, even in a population that may fail to meet the diagnostic criteria for BPD, its symptoms can become part of what the authors call the “latent landscape” (p. 148) of the disorder. Turning to practical implications, the Penn State findings can help you understand how you or someone you know who is below the BPD threshold can experience the problems in ordinary daily life that impulsivity and emptiness can create as they move up the severity scale.

To sum up, it's helpful to view BPD not as a discrete set of symptoms, but as a set of qualities that can exist below the level of a diagnostic category. Looking below the threshold may just be the key to providing help to those individuals whose symptoms create problems in living.

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Johnson, B. N., & Levy, K. N. (2020). Identifying unstable and empty phenotypes of borderline personality through factor mixture modeling in a large nonclinical sample. Personality Disorders: Theory, Research, and Treatment, 11(2), 141–150. doi:10.1037/per0000360