Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Personality Disorders
Your personality is your own way of thinking, feeling, behaving, and relating to others. Once you become an adult, your personality usually doesn't change much.
Personality disorders are a group of mental disorders. They involve long-term patterns of thoughts and behaviors that are different from what is considered normal in your culture. The thoughts and behaviors are unhealthy and inflexible. They cause serious problems with relationships, work, and social activities. They can make it hard to deal with everyday stresses and problems.
There are 10 types of personality disorders. They are grouped into three different categories called clusters. The types in each cluster have some similar symptoms and characteristics. The clusters and types are:
Cluster A personality disorders involve unusual and odd thoughts and behaviors. It includes:
- Paranoid personality disorder, in which a person has paranoia (an extreme fear and distrust of others). They may think that someone is trying to harm them.
- Schizoid personality disorder, in which a person prefers to be alone and is not interested in having relationships with others.
- Schizotypal personality disorder, in which a person has unusual thoughts and ways of behaving and speaking. They are uncomfortable having close relationships with others.
Cluster B personality disorders involve dramatic and emotional thoughts and behaviors that can keep changing. It includes:
- Antisocial personality disorder, in which a person has a long-term pattern of manipulating, exploiting, or violating the rights of others.
- Borderline personality disorder, in which a person has lots of trouble managing their emotions. This makes them impulsive and uncertain about how they see themselves. It can cause a lot of trouble in their relationships.
- Histrionic personality disorder, in which a person is dramatic, has strong emotions, and always wants attention from others.
- Narcissistic personality disorder, in which a person lacks empathy and wants to be admired by others. They think that they are better than others and that they deserve special treatment.
Cluster C personality disorders involve anxious and fearful thoughts and behaviors. It includes:
- Avoidant personality disorder, in which a person is very shy and feels that they are not as good as others. They often avoid people because they fear rejection.
- Dependent personality disorder, in which a person depends too much on others and feels that they need to be taken care of. They may let others treat them badly because they are afraid of losing the relationship.
- Obsessive-compulsive personality disorder, in which a person needs control and order. They are perfectionists and can be inflexible. Although some of the symptoms are similar, this is not the same thing as obsessive-compulsive disorder (OCD).
Personality disorders usually begin when someone is in their teens or early adult years. The cause is unknown. However, genes and childhood experiences such as abuse and trauma likely play a role.
The symptoms of each personality disorder are different. But each disorder involves problems and uncertainty with how people see themselves. The disorders also cause problems in relationships with other people.
People with personality disorders may have trouble realizing that they have a problem. To them, their thoughts are normal. They may see others as the problem. So they may not seek help when they need it. Or, if they seek help, it may be because of another reason. They may be looking for help because of other mental health symptoms or problems with relationships and work. Sometimes someone else, such as a family member or social agency, may ask them to get help.
A mental health care provider can diagnose personality disorders. A mental health provider is a health care professional who specializes in diagnosing and treating mental health problems. To make a diagnosis, the provider will consider the person's symptoms, experiences, and family medical history. A thorough medical exam may also be done to help rule out other possible causes of the symptoms.
Talk therapy, also known as psychotherapy, is the main treatment for personality disorders. Medicines may help relieve certain symptoms, such as anxiety or mood swings.
It sits within Mental Health and Behavior.
The lead U.S. institute for this subject is the National Institute of Mental Health.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Personality Disorders
660 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- Testing a Peer-led Trauma-focused Intervention for Significant Others of Those With BPDYork University
- Ketamine With Dialectical Behavioural Therapy (DBT) for Suicidality in Individuals With Treatment-Resistant Depression and Borderline Personality Disorder (KET-DBT)Joshua Rosenblat
- Testing an Alliance-Focused Dialectical Behaviour Therapy Training for Borderline Personality DisorderYork University
- A Study to Test How BI 3031185 is Tolerated by People With Borderline Personality Disorder or Attention-deficit/Hyperactivity DisorderBoehringer Ingelheim
- Integrating Exposure and Response Prevention and Habit Reversal Techniques to Treat a Tourettic Subtype of Obsessive-Compulsive Disorder (Tourettic OCD)University College London Hospitals
- Combining Transcranial Magnetic Stimulation With Emotion Regulation Skills Training in Borderline Personality DisorderMassachusetts General Hospital
Research already completed
- Caplyta in Borderline Personality DisorderUniversity of Chicago
- Development and Initial Testing of a Couple-Based Intervention to Optimize Suicide and Self-Injury Treatment: COMPASS (Connecting, Overcoming, and Moving Past Suicide and Self-Injury)York University
- Focused Versus Enhanced Cognitive Behavioral Therapy for Treating Women With Bulimia NervosaBoston University Charles River Campus
- Circuit-Based Approach to Suicide: Biomarkers, Predictors, and Novel TherapeuticsMassachusetts General Hospital
- Personality Change Study for Borderline Personality DisorderShannon E. Sauer-Zavala
- Multisystemic Therapy-Emerging Adults TrialUniversity of Massachusetts, Worcester
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Start Here
- Personality DisorderMental Health America
Treatments and Therapies
- Mental Health MedicationsNational Institute of Mental Health
- PsychotherapiesNational Institute of Mental Health
Living With
- What to Know Before Stopping Medications (Medication Discontinuation)American Association of Psychiatric Pharmacists
Clinical Trials
- ClinicalTrials.gov: Antisocial Personality DisorderNational Institutes of Health
- ClinicalTrials.gov: Personality DisordersNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Personality Disorders. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Personality Disorders, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.