Reviving the Original Meaning of Borderline
Is BPD an outdated catch-all diagnosis for all seasons or a useful severity indicator?
Posted March 10, 2026 | Reviewed by Abigail Fagan
The Borderline Personality Disorder (BPD) diagnosis was originally introduced in DSM-III as a new category separated from the other “borderline” condition of schizotypal personality disorder. Until this point, the “borderline” concept had served as a metaphor for conditions on the border to schizophrenia and mood disorders.
The “borderline” concept was, thus far, a well-established severity indicator for any marked character disorder, which was now turned into a distinct category or syndrome including diverse symptoms such as mood and identity problems, self-mutilating behavior, feelings of emptiness, and episodic aggression . In a 2016 interview, "the father" of BPD, John Gunderson, offered a candid reflection about the initial conception (and perhaps vagueness) of the BPD diagnosis:
“A group of patients that didn’t have a diagnosis, but which drove everybody crazy.”
In contrast to the unspecific borderline continuum, it became possible to use specific diagnostic criteria to recruit patients for research and treatment programs as done with other specified disease entities.
In this post, I will provide a glimpse of the last 30-40 years of research questioning the legitimacy and usefulness of the categorical BPD diagnosis. Against this background, I will illustrate how the ICD -11 and the DSM-5 Alternative Model of Personality Disorders (AMPD) capture familiar borderline features by focusing on general human aspects of personality functioning while leaving the BPD diagnosis behind for good.
A Problematic Diagnosis From the Beginning
From the very beginning, one of the APA Task Force advisors on the DSM-III classification of personality disorders, Allan Frances, disputed the meaning and usefulness of the new BPD diagnosis.
“The perpetuation of this term caused considerable controversy and resulted only from the lack of wide acceptance of any substitute term. Many feel that the concept of borderline has been so variously and loosely applied that it has lost all precise meaning and shape. It is no longer clear what it “borders” on […]. (Frances, 1980, p. 1053).
A pivotal member of the DSM-III task force, Theodore Millon (1981), criticized the term “borderline” as diagnostically misleading:
“[…] the label, borderline, is perhaps the most poorly chosen of all the terms selected for the DSM-III. I find the word, borderline, to mean, at best, a level of severity and not a descriptive type…. Unless the word is used to signify a class that borders on something, then it has no clinical or descriptive meaning at all.” (p. 331-332)
Some years after the conception of the BPD diagnosis, a major study by Fyer and colleagues (1988) concluded that BPD was an overly inclusive “catch-all syndrome.” They specifically stated that BPD is so heterogeneous and involves so much diagnostic co-occurrence that it can hardly be said to exist alone. They explicitly questioned whether BPD should be established as an independent diagnostic entity, as it suffers from a lack of clearly demarcated boundaries with no evidence of being a distinct entity.
For the same reason, it was with hesitation that the ICD-10 later on provisionally included "borderline" as a subtype of Emotionally Unstable Personality Disorder. Along the same lines, a Norwegian study found that individual BPD criteria were more closely associated with other Personality Disorder categories than with BPD itself (Johansen et al., 2004).
In more recent years, empirical sound studies have consistently challenged the notion of BPD as a distinct and clearly defined disorder (Sharp et al., 2015; Wright et al., 2016; Williams et al., 2018; Müller et al., 2025). Although the diverse “catch-all” features of the BPD diagnosis allow for easy patient recruitment for clinical trials and group therapy , the diagnostic ambiguity complicates individualized treatment and scientific progression.
Instead, recent findings on BPD features seem more aligned with a global index of mental distress closely tied to lack of resilience and fundamental trust (Fonagy et al., 2017). A reasonable interpretation of these findings and conceptualizations altogether leads us back to the original meaning of “borderline” as a metaphor for severity.
BPD as an Indicator of Severity and the New ICD-11 Era
The idea that BPD reflects a level of severity rather than a distinct personality type has deep roots in clinical theory. Otto Kernberg (1967) introduced the concept of borderline personality organization to describe a structural level of functioning between neurosis and psychosis characterized by identity diffusion, primitive defenses, and impaired reality testing — not a discrete syndrome, but a dimensional construct.
More recently, Carla Sharp (2018) called for a unified redefinition of “borderlineness”, arguing that BPD reflects underlying personality dysfunction rather than a discrete syndrome. She emphasized the lack of empirical support for BPD as a standalone category and advocated for dimensional models that better capture the complexity of personality pathology.
The following box illustrates how BPD features are contained within ICD-11's aspects of personality functioning, supporting the original meaning of “borderline” as a metaphor for global severity. The more pronounced impairment in these aspects of personality functioning, the more it resembles features of BPD.
Where Do We Go From Here?
As clinicians, researchers, and advocates, we must ask ourselves: Is BPD a “diagnosis for all seasons,” which has become a relic of an outdated diagnostic system? Or could it still be a useful metaphorical concept serving as an indicator of severity?
The move toward new models like ICD-11 and AMPD offers a promising path forward, one that respects the complexity of human personality while avoiding the pitfalls of oversimplified labels. By focusing on human personality functioning, severity, and individual trait expressions, we may better tailor treatment to individual needs and reduce the stigma associated with personality disorders.
At the same time, we must recognize the massive body of research on individuals with BPD diagnosis, including Cochrane reviews of psychological treatment and the approval by health care providers that has followed. The field must obviously seek to translate this treasure of information into future scientific and clinical use—possibly by interpreting established BPD features as a proxy for global personality dysfunction.
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Millon, T. (1981). Disorders of Personality . Hoboken: John Wiley and Sons.
Bach, B., & Simonsen, S. (2025). ICD-11 Personality Disorders: A Clinician’s Guide . Göttingen (Germany), Hogrefe Publishing Corp.
Kernberg, O. F. (1967). Borderline personality organization. Journal of the American Psychoanalytic Association, 15(3), 641–685.
Sharp, C. (2018). Calling for a unified redefinition of “borderlineness”: Commentary on Gunderson et al. Journal of Personality Disorders, 32(2), 168–174. https://doi.org/10.1521/pedi.2018.32.2.168
Tyrer, P., & Mulder, R. T. (2024). The problem with borderline personality disorder. World Psychiatry, 23(3), 445–446. https://doi.org/10.1002/wps.21249
Vaillant, G. E. (1992). The beginning of wisdom is never calling a patient a borderline; or, the clinical management of immature defenses in the treatment of individuals with personality disorders. The Journal of Psychotherapy Practice and Research , 1 (2), 117–134. http://www.ncbi.nlm.nih.gov/pubmed/22700090%0Ahttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC3330289
Frances, A. (1980). The DSM-III personality disorders section: a commentary. American Journal of Psychiatry , 137 (9), 1050–1054. https://doi.org/10.1176/ajp.137.9.1050
Gunderson, J. (2016, April 21). Interview quoted in Boston Globe obituary. https://www.bostonglobe.com/metro/obituaries/2019/02/14/john-gunderson-pioneered-defining-and-treating-borderline-personality-disorder/cqRLWPkDQXE6yEASPWPfQJ/story.html
Fonagy, P., Luyten, P., Allison, E., & Campbell, C. (2017). What we have changed our minds about: Part 1. Borderline personality disorder as a limitation of resilience. Borderline Personality Disorder and Emotion Dysregulation.
Müller, S., Schroeders, U., Bachrach, N., Benecke, C., Cuevas, L., Doering, S., Elklit, A., Gutiérrez, F., Hengartner, M. P., Hogue, T. E., Hopwood, C. J., Mihura, J. L., Oltmanns, T. F., Paap, M. C. S., Pedersen, G., Renn, D., Ringwald, W. R., Rossi, G., Samuels, J., … Zimmermann, J. (2026). Revisiting the structure of Diagnostic and Statistical Manual of Mental Disorders, fifth edition, Section II personality disorder criteria using individual participant data meta-analysis. Personality Disorders: Theory, Research, and Treatment . https://doi.org/10.1037/per0000736
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Bo Bach, Ph.D., D.MSc., is a professor of clinical psychology at the University of Copenhagen and a clinical practitioner at Slagelse Psychiatric Hospital, Denmark, where he runs the Center for Personality Disorder Research.
This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.