What Is… Borderline Personality Disorder

Borderline personality disorder symptoms

In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is borderline personality disorder.

I’ve contemplated writing this post for a while, but I was somewhat reluctant because there are quite a few bloggers out there with borderline personality disorder (BPD), who can certainly tell it a lot better than I can. However, I’ve been covering other personality disorders, and BPD isn’t a gap that I want to leave. So, let’s dive in.

According to the Merck Manual, “Borderline personality disorder is characterized by a pervasive pattern of instability and hypersensitivity in interpersonal relationships, instability in self-image, extreme mood fluctuations, and impulsivity.”

BPD is part of the DSM-5’s cluster B of dramatic/emotional/erratic personality disorders. The term borderline came about because the condition seemed to border on a number of other conditions. The International Classification of Diseases 10th edition (ICD-10) used the term emotionally unstable personality disorder (EUPD).


Borderline personality disorder symptoms include:

  • a persistent pattern of instability in relationships, self-image, and emotions, with marked impulsivity
  • desperate efforts to avoid real or perceived abandonment, which is intensely feared
  • unstable, intense relationships with splitting, i.e. alternating between idealizing and devaluing
  • instability in self-image or sense of self
  • impulsivity in at least 2 areas that could potentially be harmful
  • repeated suicidal behaviour or gestures, or self-injury
  • rapid mood fluctuations, often within the space of a few hours
  • persistent feelings of emptiness inside
  • periods of intense anger and angry outbursts, often experiencing shame afterwards
  • paranoia or dissociation under severe stress

As with any personality disorder, it’s normal for anyone to display some of these symptoms some of the time. A personality disorder is only diagnosed when the symptoms are pervasive, relatively consistent across time and contexts, clearly established by the start of adulthood, and cause significant distress and/or impairment in functioning.

Non-suicidal self-injury, i.e. self-harm, may be a way of regulating emotions or relieving feelings of numbness. Suicidal gestures are attempts where the intent is not to die, but to demonstrate that one’s pain is severe enough that they need help. While often there is not lethal intent, 8-10% of people with BPD eventually die by suicide.

Other characteristics

BPD is most often misdiagnosed as bipolar disorder. It can coexist with other personality disorders, including other cluster B disorders, but key differentiating factors from narcissistic PD and histrionic PD are that people with BPD see themselves negatively and feel empty inside.

The estimated prevalence is about 2-6% in the general population. When you look at psychiatric inpatients, about 20% have BPD. It’s more common in females (about 75% of people with BPD are female), although it’s hard to say how much of that is due to bias in diagnosing.

It’s common for people with BPD to have a history of childhood abuse or neglect, but that’s not always the case. There’s also a heritable component, with a five-fold risk increase when a first-degree relative has the disorder. DBT founder Marsha Linehan has proposed a biosocial model in which BPD arises from interactions between innate vulnerability and environmental factors.


Medications can play a role in managing some of the symptoms, but therapy is the primary form of treatment. Options include:

  • Dialectical behaviour therapy (DBT)
  • Systems training for emotional predictability and problem-solving (STEPPS), a CBT-based therapy
  • Mentalization-based treatment (MBT)
  • Transference-focused psychotherapy (TFP) – based on psychodynamic psychotherapy
  • Schema therapy


Borderline personality disorder is incredibly stigmatized, both by the world and large and by the health care field. It was certainly something I saw a lot during the 15 years I worked in mental health. I think it was largely a combination of lack of understanding and lack of skills. BPD can produce behaviours that look manipulative if you can’t recognize that they’re attempts, however maladaptive, to meet underlying needs.

Being therapeutically effective with BPD takes a skill set that a lot of people who aren’t specially trained just don’t have, but I think that instead of taking responsibility for their own lack of skills, mental health professionals too often end up blaming the patient. I’ve found that people with BPD are often very perceptive, and when they’re faced with BS from a health care provider, they can be adept at poking at exactly the spot where that provider feels vulnerable. That stirs up all kinds of countertransference on the clinician’s part, and everything falls apart.

I suspect there would be less stigma if there was more available, accessible, and effective treatment. The world of mental health care really needs to do better.

Does anyone have any thoughts on why BPD is so stigmatized?


So you've just been diagnosed with... [ mental illness]

The So You’ve Just Been Diagnosed with… [a Mental Disorder] page brings together information, advice, and resources from people who’ve been there. New input is always welcome!

Ashley L. Peterson headshot

Ashley L. Peterson


Ashley is a former mental health nurse and pharmacist and the author of four books.

57 thoughts on “What Is… Borderline Personality Disorder”

  1. Good post! I have been deeply hurt by people with BPD (1 stalked me, another basically goes on public sprees writing against my friend with DID and me) but BPD doesn’t make a person automatically abusive. I wish people would see that but they often don’t, just like the “narc abuse” community.

    Know wonderful people with BPD too. I think the stigma is the whole “personality disorder” label, it’s so pervasive even among mental health professionals who should know better.

    My blog has some really old posts ranting about that since a therapist treating complex trauma characterised abusive people to be “personality disordered”. I’ve avoidant PD and will always remember how my T said “I definitely think you meet criteria but that doesn’t mean your personality is disordered.” And of course, the risk for PDs goes up with childhood maltreatment.

    1. There’s the childhood mistreatment issue, and the component that’s inherited, yet people, including professionals, seems so quick to leap to the conclusion that people chose to have a “bad” personality that makes them abusive. People with PDs can be abusive, and so can people without. There’s no need for therapists to buy into the nonsense.

  2. Diagnostic criteria don’t capture the depths of individual experience for any diagnosis, nor do I think it would be appropriate for them to try to. Even if a given diagnostic label applies, we’re all unique individuals with unique experiences.

  3. I’ve come back to this post because I really appreciate it and I think that I may actually still meet the criteria (even more than five in the DSM) for BPD. It’s easier to say I grew out of it because I did the work it took. However, a recent abandonment wound has really brought up a lot for me. As you may have noticed recently. Anyway, thanks again for being so compassionate, when most people are not, or it seems they aren’t.

Leave a Reply