Diagnosing a personality disorder - Guideposts Trust

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Diagnosing a personality disorder

Diagnosing a personality disorder

Overview

  • A personality disorder is hard to deal with alone. Talking to a doctor or mental health professional is the first step towards getting support and treatment. If your GP feels you have a complex personality disorder, they may refer you to a:
  • community mental health team, or
  • specialist personality disorder service or unit, if there is one locally.
    There is no underlying ‘disease’ in personality disorder and there are no biological markers or signs that someone has a personality disorder. Full assessment and diagnosing ‘personality disorder’ is a task for a skilled and trained professional such as a psychiatrist or psychologist not by a GP.
    There are several steps involved in the diagnostic process, explained below:

In-depth assessment

The first step in diagnosing personality disorder is a full assessment. The mental health professional carrying out the assessment will ask you a range of questions about your symptoms and life experiences. They might also want to speak to your friends and family so it can take a while to reach a firm diagnosis. Assessments normally take place over a number of sessions.
The assessment will cover:

  • your current difficulties including mental health symptoms and experiences
  • your feelings, thoughts and behaviours
  • your physical health and wellbeing
  • your social circumstances: housing, finances/debt, employment, support network, if you are a parent or carer, your culture and ethnic background, gender and sexuality (where relevant)
  • your personal and family history including relationships
  • your use of drugs or alcohol
  • past experiences, especially of similar problems and previous treatments
  • risk assessment
  • your goals for therapy – what you wish to work on or changes you wish to make

Diagnostic criteria for a personality disorder

Mental health professionals use guidelines for diagnosing mental health problems. The main guidelines are:

  • International Classification of Diseases (ICD-11) produced by the World Health Organisation (WHO), and
  • Diagnostic and Statistical Manual (DSM-5) produced by the American Psychiatric Association.
    When making a diagnosis, mental health professionals think about your symptoms and behaviours and compare them to the guidelines. To meet the threshold for being diagnosed with a personality disorder, DSM specifies that a person must have a certain number of the possible characteristics for that disorder (often 4 or 5 out of 8 or 9 possible characteristics). A diagnosis of personality disorder cannot be made on the basis of just one or two features.

In general in the UK 8% of the population would meet the criteria for a diagnosis of personality disorder (1 in 12 people). This means this is quite common.

Difficulties in making a diagnosis

Mental health professionals may find it difficult to diagnose personality disorder. Reasons include:

  • symptoms are very broad, often very similar to other mental health conditions, which makes personality disorders complex to understand.
  • it can be difficult to determine the type of personality disorder, as some personality disorders share similar symptoms and more than one type may be present.
  • other disorders such as depression, anxiety or substance abuse may further complicate diagnosis.
  • some doctors are reluctant to give this diagnosis, feeling that it may be ‘problematic’ or make it harder for someone to get help.

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