How to Tell If Your Character Has Borderline Personality Disorder

Let me ask you a question: what do you know about borderline personality disorder? If you think BPD is about attention-seeking or only impacts women, it’s time to set the record straight.

We all go through periods when our emotions feel raw, but with borderline personality disorder (BPD), this rawness doesn’t just fade away with time. Emotions continue to be sensitive, like a badly healed cut, and understanding the consequences of this can help you to write a more riveting, representative and sensitive portrayal of BPD in your story.

Ready to learn more? Then let's take a closer look at how borderline personality disorder is diagnosed, what makes its development more likely and how it differs from other mental health disorders.

To Keep in Mind:

The information in this post comes from the DSM-5 (see ‘Further Reading’). Please do not use it to diagnose yourself or others. It isn’t intended to be a substitute for professional advice so do consult a qualified clinical professional if you have any questions about the diagnosis criteria. Feel free to use this information to learn more about your characters, however!

Borderline personality disorder (also known as emotionally unstable personality disorder) is a Cluster B personality disorder characterised by a pattern of intense and explosive emotions.

Individuals with this personality disorder tend to experience severe, unpredictable mood swings, fluctuating between powerful positive and negative feelings within a short time frame. Emotions are felt much more deeply: despair rather than sadness, rage rather than annoyance, panic rather than anxiety. Regulating emotional levels is that much harder, and self-harm and suicide attempts are fairly common.

So how do you go about writing a character with BPD? Start by learning the diagnostic criteria.

How Is Borderline Personality Disorder Diagnosed?

To be diagnosed with BPD, your character must display five or more of the following characteristics:

  • Makes frantic efforts to avoid abandonment, whether real or imagined. (Note: This doesn’t include self-harm or suicide attempts, covered below.)
  • Has a pattern of intense and unstable relationships that swing between the extremes of idealisation and devaluation.
  • Has an identity disturbance, with an unstable self-image or sense of self.
  • Acts impulsively in two potentially self-damaging areas, such as abusing drugs, having unsafe sex, driving dangerously, spending recklessly, binge eating, and so on. (Note: This doesn’t include self-harm or suicide attempts.)
  • Repeatedly self-harms (e.g., cutting), makes suicide threats or gestures, or attempts suicide.
  • Experiences emotional instability that causes severe mood swings, which can last anywhere from a few hours to (more rarely) a few days.
  • Feels empty, worthless or lonely on a chronic basis.
  • Feels sudden, intense and often uncontrollable anger or aggression, which can lead to a loss of temper or physical fights, or showing this anger in inappropriate ways or situations.
  • Feels paranoid or disconnected from the world, their body, thoughts or behaviour when stressed.

Another thing to keep in mind: the characteristics listed above must be stable, inflexible and constant throughout different situations. What does that mean? If your character only acts this way once, in just one circumstance, then it wouldn’t be enough to diagnose them with BPD. This is an integral part of their personality, pervading their thoughts, actions and emotions, something you need to remember if you write about borderline personality disorder.

As only five of the nine characteristics listed above need to be present to be diagnosed, what one person with BPD experiences may be different to another. What should you take from that? There’s not just one set way to portray a character with borderline personality disorder. Read widely, research thoroughly and find out what it’s really like for someone living with BPD, not just what popular media says it is.

What Makes Borderline Personality Disorder More Likely?

Age and Gender

While more women are diagnosed with BPD (around 75% of cases), don’t make the mistake of thinking it doesn’t affect other genders. It may well be that fewer men seek treatment for BPD or that it’s recognised less frequently in men, leading to fewer diagnoses. (In other words, a character with borderline personality disorder does not have to be female.)

What about age? Early adulthood is commonly when serious emotional and impulsive dyscontrol occurs, as well as higher risk of suicide or impairment from the disorder. The nature of personality disorders means that the symptoms are enduring and long-lasting, but the risk of harm and instability from BPD tends to lesson with age, especially after therapeutic intervention.


Certain factors can make a person more likely to develop BPD. One such factor is neuroticism, or the tendency to feel strong, long-lasting negative emotional states. This can leave someone open to BPD, as can hyper-sensitivity. These factors make learning to manage and regulate emotions difficult, leading to the characteristics listed above.

Other personality factors associated with borderline personality disorder are low levels of agreeableness and conscientiousness. (Find out more about these personality traits, plus others, in Design a Personality: Building Rock-Solid Character Traits.)

Personal History and Attachment Style

Borderline personality disorder is often found in those who experienced neglect and abuse, particularly sexual abuse, in childhood, or in those whose parents ignored their feelings and withdrew from them, leaving the child feeling unprotected.

Also more likely to develop BPD are people with insecure-avoidant, insecure-resistant, and disorganised-disoriented attachment styles. (Find out what these attachment styles, formed in early childhood, are in Your Character’s Very First Relationship (Hint: It Affects All the Others))

So that’s a glimpse into what makes up borderline personality disorder. Bear those diagnosis criteria in mind when checking out Intense and Emotional: Writing About Borderline Personality Disorder, where we’ll take a look at what exactly is meant by each of the behaviours listed and how we can use them to write about characters whose emotional outbursts leave characters and readers reeling.