What Is A Personality Disorder?

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Personality disorders are a group of complex mental health conditions that can affect an individual’s behaviour, thoughts, and feelings long term, with the latest Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) currently recognising 10 specific types of personality disorders, all with their own distinct criteria.

People with a personality disorder can have difficulty building relationships and managing their emotions, as well as with their general mental health. Currently, it is estimated by the Mental Health Foundation that around 1 in 20 people in the UK are diagnosed with a personality disorder. However, people with personality disorders are often reluctant to seek out medical help, so many cases may go undiagnosed. For this reason, the actual prevalence may be much higher.

Most treatments for personality disorders aim to reduce the impact of these disorders on your life. Additionally, you may be prescribed medication to treat other mental health disorders that individuals with a personality disorder often experience such as depression or substance misuse. 

Read on to learn more about the causes, the different types of personality disorders and how clinicians manage them. 

Causes of personality disorders

Currently, there is no clear consensus as to why some people develop personality disorders. Most researchers agree that it arises from a combination of genetic components and early environmental factors. Adverse experiences during childhood, such as abuse, can significantly increase your risk of developing a personality disorder. It is important to note that personality disorders still develop without adverse experiences during childhood. 

Signs and symptoms of personality disorders

Signs and symptoms not only vary greatly depending on the type of personality disorder you are facing but also between individuals.

Typically, personality disorders begin to emerge in the teenage years and young adulthood.

DSM-5-TR categorises personality disorders into 3 clusters. This helps us to better identify and treat the symptoms associated with personality disorders.

Cluster A (Suspicious)

Cluster A personality disorders include the following:

Paranoid personality disorder (PPD) is characterised by a long-term pattern of thoughts and feelings that make it hard to trust other people, as well as interpret dangers in everyday situations.  Of note, individuals with PPD don’t experience delusions like those seen in schizophrenia or bipolar disorder.

Individuals with PPD may experience these symptoms:

  • Find it difficult to relax
  • General mistrust of people
  • The belief that others are trying to exploit or deceive them

Schizoid personality disorder is a condition where people avoid interactions and social activities, as well as building relationships with others, such as family members. People who are diagnosed with this disorder may appear cold due to a lack of displaying emotion.

Individuals with schizoid personality disorder may experience these symptoms:

  • Difficulty forming relationships
  • Prefer being alone
  • Anhedonia (inability to feel pleasure)
  • Little interest in sex or intimate relationships

Schizotypal personality disorder is characterised by eccentric behaviour. People diagnosed with this disorder often find it difficult to relate to others.

Individuals with schizotypal personality disorder may experience these symptoms:

  • Delusional thoughts
  • Finding it difficult to make close relationships
  • Feeling anxious and tense when others don’t share your beliefs

Cluster B (Emotional and impulsive)

Dramatic and unpredictable symptoms are observed in individuals with a cluster B personality disorder.

People with antisocial personality disorder often put themselves before anyone else. They may act dangerously and illegally.

People with antisocial personality disorder may:

  • Have a criminal record
  • Behave in ways that are unpleasant to others
  • Put themselves in dangerous situations

Borderline personality disorder (BPD) can also be referred to as emotionally unstable personality disorder (EUPD). Prevalence estimates range from 0.7% to 2% among the UK general public, making it the most common personality disorder diagnosed in the UK. Self-image issues, unstable interpersonal relationships and intense emotions characterise BPD.

Individuals with BPD may experience the following symptoms:

  • Emotional instability
  • Disturbed patterns of thinking or perception
  • Impulsive behaviour
  • Intense but unstable relationships with others

People with narcissistic personality disorder typically appear selfish as they put their needs above others.

They may:

  • Have delicate self-esteem; they need praise from those around them.
  • Get upset when others do not give them attention.
  • Be selfish and fail to recognise other people’s needs.
  • Believe they are special and more important than others.
  • Be arrogant

Histrionic personality disorder is characterised by the need to be noticed. Individuals with histrionic personality disorder  struggle with not being the centre of attention when socialising.

Individuals with histrionic personality disorder may experience the following symptoms:

  • Uncomfortable when they are not the centre of attention
  • Excessively emotional or sexually provocative in order to remain the centre of attention.
  • Influenced by others easily
  • Excessive concern with physical appearance
  • Feels the need to entertain others

Cluster C (Anxious)

Avoidant personality disorder (AvPD) is characterised by excessive anxiety that makes it difficult to maintain relationships. It is also known as anxious personality disorder.

Those with AvPD may:

  • Avoid situations where they have to socialise.
  • Avoid relationships because they fear rejection.
  • Afraid to start new activities because they think they might embarrass themselves.
  • Feel lonely
  • Constantly worry about being ‘found out’ and then subsequently being rejected.

Obsessive-compulsive personality disorder (OCPD) describes a type of personality, whereas obsessive-compulsive disorder (OCD) describes a behaviour.

Sufferers of OCPD may:

  • Be preoccupied with needing to keep everything perfect and under control, and get anxious if this isn’t the case.
  • Exhibit perfectionism, which impedes their  ability to complete tasks
  • Feel a desire for order
  • Insist on doing things their way.
  • Worry about both themselves and others making mistakes
  • Be severely self-critical

Dependent personality disorder is characterised by an over-reliance on others, resulting in submissive and clinging behaviour. Many people with a dependent personality disorder will agree to ideas that they dislike because of a fear of losing the support of others.

Individuals with a dependent personality disorder may experience the following symptoms:

  • Low self-confidence
  • Unable to make decisions or function on a daily basis without input or support from others.
  • Fear of abandonment
  • Needs an individual to take responsibility for most aspects of their life.

Additionally, there is a condition known as Personality disorder not otherwise specified (PD-NOS). This diagnosis is given when you fail to meet the criteria for a specific personality disorder. People with PD-NOS may experience the traits of multiple personality disorders. 

Management and treatment for personality disorders

The best treatment for personality disorders depends greatly on the type of personality disorder you have been diagnosed with as well as its severity. A mental health professional will be able to create an individualised treatment plan.

Talking therapy

Talking therapy, also known as psychotherapy, is the gold-standard treatment for personality disorders. A healthcare professional can help you to determine which talking therapy is best for you.

Dialectal behavioural therapy (DBT)- is a treatment that was specifically designed for BPD. It utilises both group and individual therapy to teach skills so that individuals with BPD can better manage their emotions.

  • Mentalisation-based therapy (MBT) - is another form of talking therapy that aims to help individuals think about and understand their mental state. Additionally, it allows individuals to examine if their thoughts are valid.
  • Cognitive behavioural therapy (CBT) - aims to aid individuals in understanding how their thoughts affect their behaviour and feelings.
  • Structured Clinical Management (SCM) - is used as an alternative treatment for people with personality difficulties. Researchers have found it to be as effective as other forms of specialist treatments such as DBT and MBT3. It is an evidence-based treatment that allows mental health practitioners to work with those with personality disorders. 
  • Family therapy - If a loved one has a personality disorder it be can helpful for family members affected by personality disorders to attend this treatment. It helps family members to develop coping strategies, thus helping the family to work together more effectively.

Therapeutic communities

Therapeutic communities are where individuals with a personality disorder can attend an intensive form of group therapy for an extended period of time. Whilst there they can discuss their personal experiences of having a personality disorder.


There is currently no drug treatment specifically for personality disorders. However, medication is commonly prescribed to treat disorders that are associated with personality disorders, such as depression, eating disorders, psychotic symptoms, and substance misuse.

For example, antidepressants such as selective serotonin reuptake inhibitors (SSRIs) are often used to treat moderate to severe symptoms of depression, which can often occur alongside personality disorders. Research has shown that treatment with an SSRI may improve traits of personality disorders.1


What are the types of personality disorders?

There are 10 types of personality disorder recognised by the DSM-5-TR.

  1. Antisocial personality disorder
  2. Avoidant personality disorder
  3. Borderline personality disorder
  4. Dependent personality disorder
  5. Histrionic personality disorder
  6. Narcissistic personality disorder
  7. Obsessive-compulsive personality disorder
  8. Paranoid personality disorder
  9. Schizoid personality disorder
  10. Schizotypal personality disorder

Additionally, there is a condition known as Personality disorder not otherwise specified (PD-NOS). 

How are personality disorders diagnosed?

To receive the appropriate treatment, you need to get a diagnosis from a healthcare professional with specialist training in diagnosing personality disorders.

Various methods can be utilised for the clinical diagnosis of personality disorders. They include: 

  • A physical exam
  • Psychiatric evaluation
  • Criteria stated in the DSM-5

It is important to note that individuals under the age of 18 are not usually diagnosed with personality disorders as their personalities are still under development. 

Can personality disorders be prevented?

Since there is no definitive answer to what causes personality disorders, it is hard to develop early intervention strategies.

However, there may be some things that you can do to help:

  • Validate your children’s emotions
  • Prevent childhood abuse
  • Being present

Who is at risk of developing personality disorders?

Researchers believe some factors increase your risk of developing personality disorders. These include:

  • Family history of personality disorders
  • An abusive or unstable childhood
  • Variations in brain chemistry and structure
  • Individuals diagnosed with childhood conduct disorder 

How common are personality disorders?

The prevalence of all personality disorders is 9.1% among US adults aged 18 and over. Additionally, the prevalence of borderline pesonality disorder among the US population is believed to be 1.4%2.

When should I see a doctor?

If you suspect that you may have a personality disorder, your first step should be contacting your doctor. They will be able to discuss your symptoms and refer you to a specialist who can carry out a personality disorder assessment. If your personality disorder remains untreated, it can significantly impact your day-to-day life as well as your loved ones. 


Personality disorders are a group of mental health conditions that affect an individual's behaviour, thoughts and feelings. According to DSM-5, there are currently 10 specific personality disorders, as well as a condition known as PDNOS. Although researchers are unsure of the exact cause of personality disorders, there is an  agreement that they are caused by a combination of genetic components and early environmental factors. Seeking medical advice if you suspect that you may have a personality disorder is the best way of getting help. With the correct treatment and support, people with personality disorders are capable of living fulfilling and happy lives. 


  1. Fava M, Farabaugh AH, Sickinger AH, Wright E, Alpert JE, Sonawalla S, et al. Personality disorders and depression. Psychological Medicine. 2002;32(6): 1049–1057. https://doi.org/10.1017/S0033291702005780.
  2. Lenzenweger MF, Lane MC, Loranger AW, Kessler RC. Dsm-iv personality disorders in the national comorbidity survey replication. Biol Psychiatry. 2007 Sep 15;62(6):553–64.

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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