for better mental health

Personality disorders

Explains personality disorders, including possible causes and how you can access treatment and support. Includes tips for helping yourself, and guidance for friends and family.

This page is also available in Welsh (Cymraeg).

What causes personality disorders?

Just as everybody's experience of a personality disorder is unique to them, the causes will be unique as well.

There's no clear reason why some people develop the feelings and behaviours associated with personality disorders, and others don't. Most researchers believe that a complex mix of factors seems to increase the risk of developing or triggering these experiences, including:

Environment and social circumstances

The environment and social circumstances we grow up in and the quality of care we receive can affect the way our personality develops. You may experience difficulties associated with personality disorders if you've experienced:

  • an unstable or chaotic family life, such as living with a parent who is an alcoholic or who struggles to manage a mental health problem
  • little or no support from your caregiver – this may be especially hard if you've experienced a traumatic event or situation
  • a lack of support or bad experiences during your school life, peer group or wider community, such as bullying or exclusion
  • poverty or discrimination
  • some form of dislocation, such as migration from abroad.

"I have narcissistic borderline personality disorder. At first it was difficult to accept that the problem was essentially me, my personality. But then being able to put it into perspective as a developmental flaw was much easier to accept – that it was simply the way I'd developed in response to my environment and the situations I'd experienced."

Early life experiences

Our experiences growing up can affect our personality in later life. If you had a difficult childhood, you might have developed certain beliefs about the way people think or act and how relationships work. This can lead to developing certain strategies for coping which may have been necessary when you were a child, but which aren't always helpful in your adult life.

If you have been given a personality disorder diagnosis you are more likely than most people to have experienced difficult or traumatic experiences growing up, such as:

Not everyone who experiences a traumatic situation will develop these problems however. Your unique reactions, as well as the consistency and quality of support and care you received, will make a difference.

Similarly, not everyone who develops a personality disorder will have had a traumatic experience.

Genetic factors

Personality is very complex and researchers currently don't know much about what makes up our personalities and to what extent genes play a part in this.

Some elements of our personality are likely to be genetic. We are born with different temperaments – for example, babies vary in how active they are, their attention span and how they adapt to change.

While some experts believe genetic inheritance may play a part in the development of personality disorder, others point out that it is difficult to know whether similarities in temperament and behaviour have been handed down the generations genetically or through the behaviour children were modelled as they grew up. More research needs to be done in this area.

This information was published in January 2020. We will revise it in 2023.

References are available on request. If you would like to reproduce any of this information, see our page on permissions and licensing.

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