What is Borderline Personality Disorder?

Reina Stewart & Cassandra Turner

May 31st 2019 


What is BPD?

Borderline personality disorder has been recognized by the American Psychiatric Association as a mental illness since 1980, when it was first described in the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). The core symptoms of BPD involve:

  • Emotional Instability
  • Interpersonal Instability
  • Behavioural Instability


Emotional Instability

Experiencing intense emotions and being emotionally sensitive are fundamental components of this disorder. Often people with BPD report that they struggle to manage their emotions, feel anxious or worried, get intensely angry, or feel chronically depressed or empty [1]. The anxiousness that individuals with BPD feel is often rooted in relationship stresses and worries related to potential negative interpersonal outcomes [1]. Similarly, the experience of separation insecurity includes the fear of rejection in close relationships [1]. Depression, which is also a facet of negative affectivity, establishes the foundation for chronic feelings of low self-worth, as well as suicidal ideation and behaviour that are disproportionately high in people with BPD [1]. Individuals with BPD can also experience instability in their sense of identity or self-image, for instance feeling like their values and aspirations are always changing [1].


Interpersonal Instability

Just like most humans, people with BPD value close relationships, trust, and support. However, as Marsha Linehan pointed out, many individuals with BPD “simply cannot regulate themselves”, and may look to others for help managing their emotions [2]. This can make the stakes in relationships feel very high, and people with BPD can feel especially vulnerable or sensitive to cues that person might be rejecting their ideas, feelings, or companionship. Because their relationships are so important for their emotional well-being, people with BPD can spend a lot of time worrying about actual or imagined abandonment [1]. Laboratory and naturalistic studies show that, when interacting with others, people with BPD often exhibit attentional and attributional biases, for instance misinterpreting someone’s behaviour as angry or critical, that can result in more intense emotions. Over time, this interpersonal sensitivity can make it difficult to form and maintain positive relationships [1]. Close relationships tend to be unstable, intense, and involve a high degree of conflict [1]. At times, people with BPD might ask for a lot of closeness, to the point that others become overwhelmed by their needs. At other times, they may withdraw from others and rebuff people’s attempts to provide support. People who meet the criteria for BPD frequently perceive relationships in either an idealized or devalued manner, meaning that relationships feel “all good” (the best relationship I’ve ever had!) or “all bad” (the worst relationship I’ve ever been in) [1].


Behavioural Instability

Another feature of BPD is disinhibition, which consists of impulsivity and risk taking [1]. Many people with BPD engage in impulsive and risky actions that may cause them harm, for example, substance abuse or non-suicidal self-injury. Linehan noted that many of the impulsive and risky behaviours in which those with BPD engage work to regulate emotions [2]. However, Linehan also made clear that while these actions might make a person feel better in the short-term, they do not provide long-term solutions to emotional suffering [2].

The Risky Behaviour Lab focuses on understanding many of the behaviours and symptoms that are commonly experienced by people with BPD. You can learn more about our research here and here.


How does BPD affect people?

BPD affects people in various ways. This personality disorder has been described as the “I don’t fit in disorder” [2], which indicates interpersonal relationships can be especially problematic for those with BPD. As discussed above, the combination of interpersonal, emotional, and behavioural difficulties all impact the relationships and well-being of those with BPD. Emotion dysregulation, resulting in uncontrollable anger and irritability, as well as alternating between idealizing and devaluing a partner or friend, puts strain on personal relationships. It is common for those with BPD symptoms to desire intimacy and attachment, but at the same time find it difficult to trust their partners [4]. Often romantic relationships are the most challenging to maintain, and it is common for these relationships to consist of low levels of satisfaction and increased rates of anxiety and conflict [4].   

This disorder is also associated with high rates of suicidal thoughts, attempts, and death [3]. Roughly 10% of people with BPD die by suicide, and up to 70% engage in non-suicidal self-injury [3]. An individual with BPD is likely to suffer from other mental health issues, such as depression, substance use disorders, and social phobia [5].

Even though a high amount of distress is associated with BPD symptoms, recovery is possible and many people with BPD lead full and happy lives. In one study, it was found that 70% of people with BPD no longer met criteria for the disorder after 6 years [6]. Marsha Linehan is a therapist and researcher who has spoken publicly about her struggle with BPD, and how she has used her experiences to pioneer treatments that help people create a life worth living. Other stories of recovery can be found here, here, and here.


How and why do people get BPD?

Biological and environmental factors influence the development of many mental health disorders, including BPD [7]. According to Marsha Linehan’s biosocial model of BPD, understanding the development of BPD involves looking for patterns of transactions between a person’s behaviors and the environments’ response that get more rigid or intense over time. Psychologists have shown that we can identify a person’s temperament very early in life. For instance, some babies seem to be naturally calm and happy most of the time, and when they get upset they are easily comforted. Other babies are more sensitive to their environments, startle or get upset more easily, and may take longer to soothe when they are upset [7]. These early temperaments interact with social and psychological factors over the course of development [7]. For instance, parents of hard-to-soothe babies might feel stressed and anxious, making it harder for them to effectively comfort their child. Over time, the child may start showing more and more intense distress as a way to signal to the parent their need for comfort, and parents may increasingly struggle to understand and respond to the intense emotional displays of their child. In this way, a biological predisposition lays the foundation for the development of this disorder, and environmental circumstances may increase the risk of experiencing BPD symptoms.

In regards to the causes of BPD, it is important to note that:

Individual diversity in specific areas of the brain may contribute to differences in severity of impulsive behaviour and emotional instability, as well as how events are generally perceived [7].

Increased rates of BPD, and mental health disorders in general, have been found among family members, which could suggest genetic influences and/or social learning [7].

Even though traumatic childhood experiences may contribute to the development of BPD, some children who grow up in a supportive setting may still develop BPD, just as many children who live in a neglectful environment may never develop BPD [7].


What kinds of treatments are available for BPD?

Treatments for BPD can be highly effective, and people do recover [6]. To decrease the effect of specific BPD symptoms, different medications may be prescribed [5]. However, there is no single medication that treats the overall symptomatology [5]. There are various forms of psychosocial therapies available for those who meet the criteria for BPD [5]. The different treatment approaches may include:

  • Dialectical Behaviour Therapy (DBT)
  • Mentalization-based therapy (MBT)
  • Cognitive Behavioural Therapy (CBT)
  • Systems training for emotional predictability and problem-solving (STEPPS)
  • Schema-focused Therapy
  • Transference-focused psychotherapy (TFP)

A description of these types of psychotherapies may be found on this site.

Where can I find out more?

Information, resources, and recommendations for learning about and managing BPD is available from:


[1] American Psychiatric Association. (2012). DSM-IV and DSM-5 Criteria for the Personality Disorders.

[2] New York-Presbyterian Hospital. (2012, February 2). Back From the Edge – Borderline Personality Disorder. 

[3] Borderline Personality Disorder Society of British Columbia. (2017, May 14). What is BPD?. 

[4] Lazarus, S. A., Scott, L. N., Beeney, J. E., Wright, A. C., Stepp, S. D., & Pilkonis, P. A. (2018). Borderline personality disorder symptoms and affective responding to perceptions of rejection and acceptance from romantic versus nonromantic partners. Personality Disorders: Theory, Research, And Treatment, 9(3), 197-206. doi:10.1037/per0000289

[5] The Centre for Addiction and Mental Health. (2010, February 3). Borderline Personality Disorder. 

[6] Zanarini, M. C., Frankenburg, F. R., Hennen, J., Silk, K. R. (2003). The longitudinal course of borderline psychopathology: 6-year prospective follow-up of the phenomenology of borderline personality disorder. American Journal of Psychiatry, 160(2), 274-283.

[7] Hebblethwaite, C., Waller-Vintar, J., Anderson, P., Leung, N., and Harris, C. (2009). About borderline personality disorder. In borderline personality disorder: an information guide for families.

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