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Borderline personality disorder

About borderline personality disorder

What is borderline personality disorder?

Borderline personality disorder (BPD) is a mental illness that:

  • makes it hard for a person to feel comfortable in themselves
  • causes problems controlling emotions and impulses
  • causes problems relating to other people.

People with BPD have high levels of distress and anger.

They can easily take offence at things other people do or say.

People with BPD might struggle with painful thoughts and beliefs about themselves and other people. This can cause distress in their work life, family life and social life. Some people with BPD harm themselves.

For most people with BPD, symptoms begin during their teenage years or as a young adult, then improve during adult life.

BPD is a condition of the brain and mind. If someone has BPD, it is not their fault and they did not cause it.

Why is it called ‘borderline’?

The name of this illness includes the unusual word ‘borderline’ for historical reasons.

In the past, mental illnesses were categorised as ‘psychoses’ or ‘neuroses’. When psychiatrists first wrote about BPD, it didn’t fit into either category. They decided it belonged on an imaginary line between these two groups of illnesses.

What causes borderline personality disorder?

The exact causes of BPD are not yet known. It is probably caused by genes as well as experiences – not just one or the other.

For a person who is naturally very sensitive, life problems while growing up might be especially damaging. These problems could include bad experiences or having another mental health condition.

It is not possible to predict who will develop BPD.

Symptoms of borderline personality disorder

Someone with BPD will have several of these signs or symptoms:

  • Being prone to fear that other people might leave them. This can cause them to make frantic efforts to avoid being abandoned by other people – including in situations where other people wouldn’t feel let down or wouldn’t take it personally.
  • Having relationships that are unusually intense and unstable (e.g. idealising another person, then intensely disliking them).
  • Being very unsure about themselves – not really knowing who they are or what to think about themselves.
  • taking risks or acting impulsively in ways that could be harmful (e.g. not thinking before spending money, risky sexual behaviour, risky drug or alcohol use, driving recklessly or binge-eating).
  • Repeatedly harming themselves, showing suicidal behaviour, or talking and thinking about suicide.
  • Experiencing short-lived but intense emotional ‘lows’ or times of irritability or anxiety. This is usually only for a few hours at a time but sometimes this can last longer.
  • Experiencing a persistent feeling of being ‘empty’ inside.
  • Experiencing anger that is unusually intense, and out of proportion to whatever triggered the anger, and being unable to control it (e.g. having fits of temper or getting into fights).
  • When stressed, becoming highly suspicious of others or experiencing unusual feelings of being detached from their own emotions, body or surroundings.

Getting help for borderline personality disorder

The sooner you get help, the more chance you have of getting the correct diagnosis and getting effective treatment and help to manage your problems.

Where to get help – Australia

  • Your GP (family doctor) – a GP can refer you to a public mental health service or a private psychiatrist, psychologist or private hospital clinic.
  • headspace – Australia’s National Youth Mental Health Foundation.
  • Your local mental health service – assessment and treatment at public mental health centres is free.

Where to get help – New Zealand

  • Your GP (family doctor) – a GP can refer you to a public mental health service or a private psychiatrist, psychologist or private hospital clinic.
  • Your District Health Board.

More about the first steps to get help

How is borderline personality disorder diagnosed?

There is no test for BPD. It can only be diagnosed by a mental health professional after talking to the person and getting to know them.

The diagnosis of BPD can be made if a person has several of the signs or features. There are many combinations of these features, so people with a diagnosis of BPD can seem very different from one another.

If someone has signs of BPD, their doctor or psychologist will carefully ask questions about their life, experiences and symptoms before making the diagnosis. It could take more than one session to be sure of the diagnosis, because some of the symptoms of BPD are similar to the symptoms of other mental health conditions.

BPD is usually not diagnosed in children before puberty.

How is borderline personality disorder treated?

Psychological treatments (talking therapies) are the best way to treat BPD. These treatments usually involve talking with a health professional one-to-one, or sometimes attending special groups.

Medication is not recommended as a person’s main treatment for BPD.

More about treatment of borderline personality disorder

Recovery from borderline personality disorder

With treatment, most people with BPD recover from their symptoms for at least some of the time. If someone recovers there’s a good chance they won’t develop symptoms again.

Most people find that their symptoms improve within a few years after getting the diagnosis.

Many people achieve a good social life and work life. Some people still have some problems with work and social life, even though their symptoms have improved.

Myths about borderline personality disorder

Myth: There is no such thing as BPD.
Myth: People with a diagnosis of BPD really have post-traumatic stress disorder (PTSD).
Myth: A person with BPD should not be told their diagnosis.
Myth: BPD is always due to child abuse.
Myth: BPD cannot be treated.
Myth: The only effective treatment for BPD is very long-term psychological treatment (psychotherapy).

More information and support


New Zealand


  • Borderline personality disorder (BPD) is a mental illness that makes it hard for a person to feel comfortable in themselves, causes problems controlling emotions and impulses, and causes problems relating to other people.
  • BPD is a condition of the brain and mind. It is not the person’s fault and they did not cause it.
  • BPD is a treatable condition and most people with BPD can recover.
Page last reviewed Dec 2020 | C1038V1

This is a general guide only, and does not replace individual medical advice. Please speak to your doctor for advice about your situation. The RANZCP is not liable for any consequences arising from relying on this information. Subject matter experts, people with lived experience of mental illness and carers all contributed to this fact sheet.