Personality and Personality Disorders

The term personality refers collectively to all traits or characteristics that determine how people usually think and feel about themselves, relate to others, and respond to the world around them. A personality disorder may be present when a person's usual way of relating to others, thinking about the world, and responding to events causes him or her to have problems that interfere with important areas of life, including education, employment, and relationships with other people.

Three Neighbors

Renée is a warmhearted, energetic woman who knows everyone in the neighborhood. She is always ready to lend a hand or a tool from her well-stocked garage. She loves to organize neighborhood activities. Renée hosts backyard cookouts, plans the yearly spring cleanup and planting of the neighborhood park, and serves mugs of hot chocolate when neighbors shovel snow from the walks in winter. People say that Renée is friendly, outgoing, and enthusiastic.

Rudy, who lives at the end of the block, annoys everyone with his grouchy mood and self-centered attitude. He scowls at the neighborhood kids who walk past his house, warning them not to step on his lawn and scolding them to keep the noise down as they get off the school bus on his corner. People say Rudy is selfish, impatient, and bad-tempered.

What Is Personality?

The brief descriptions of these three neighbors highlight some of the ways in which they are different from one another. They capture a few of the main characteristics of each person. These characteristics are what psychologists * call personality traits.

Personality traits shape or label the ways people usually think and feel about themselves (such as insecure, self-centered, or humble); how they relate to others (such as suspicious, critical, or friendly); and how they respond to events (such as accepting, fearful, or short-tempered). Personality is an individual's own special blend of these traits. Although each person has a unique personality, there are some groups of personality traits that produce recognizable personality styles.

Some normal and common personality styles have been described with terms such as self-confident, dramatic, sensitive, leisurely, adventurous, solitary, and aggressive. Personality style influences how someone thinks, feels, and behaves in most situations. Well-adjusted people are usually able to adapt to situations that call for a way of thinking or responding that is different from their usual personality style.

Some individuals have a personality style that leads them to have serious problems in most areas of their lives. Such individuals are often set in their ways and inflexible. They tend to be unable to adjust to the demands of a situation that calls for a different way of responding. Such a problematic personality style may qualify as a personality disorder. There are 10 different personality disorders that mental health professionals in the United States and Canada may diagnose. A personality disorder has a harmful effect on most aspects of the person's life, leading to long-term difficulties in relationships with other people.

What Are Personality Disorders?

Personality, or personality style, describes someone's usual pattern of thinking, feeling, and behaving. Personality style is made up of a number of traits or characteristics. A personality disorder is a problematic personality style that negatively affects most areas of a person's life.

Personality disorders are not to be confused with personality tendencies. As the following information indicates, a person can demonstrate characteristics of a personality disorder at any given time. An occasional loss of temper or inappropriate display of emotion does not mean that the person has a personality disorder. When a personality disorder is identified, it can cause lifelong psychological problems and difficulty in relating to others.

The Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) is used by mental health professionals in North America to diagnose personality disorders as well as other mental disorders. DSM-5 identifies 10 different personality disorders. Each has its own set of characteristics, and each causes problems of a certain nature. The 10 personality disorders fall into three groups called clusters, based on similarities in the personality traits of the disorders in each group.

One cluster includes personality disorders that feature unusual points of view or odd or eccentric behavior of various sorts. In this cluster are the following disorders:

Another cluster includes personality disorders that feature personality styles that are overly dramatic, overly emotional, overly reactive, or unpredictable. In this cluster are the following disorders:

A third cluster includes difficult personalities that feature anxious, fearful, or extremely cautious behavior. In this cluster are the following disorders:

How Are Personality Disorders Diagnosed?

Personality disorders are difficult to diagnose because many of these traits are also found in normal personalities. A personality disorder is diagnosed only when a personality trait, or a set of traits, is present to such an extent that it causes an individual to have problems almost every day in almost all interactions.

Several of the personality disorders have traits that overlap, making it difficult to distinguish them. Evaluating personality styles can be subjective, and different people may have different ideas about each personality style. Even experts may not agree about whether a certain trait in an individual is extreme or simply a variation of normal. When some people have problems as a result of trauma or other difficult events in their lives, they may appear to have problems affecting most parts of their lives. Generally these problems are temporary. Researchers have continued to work on finding new ways of classifying and diagnosing personality disorders that will be more reliable and accurate.

What Causes Personality Disorders?

Because each personality disorder is different, there are separate theories about how each one might develop. There is still much to learn about the factors involved in each of these disorders. Most theories focus on a combination of inborn * traits and early experiences that influence and shape how someone begins to think, feel, and act. Research has shown that being a victim of child abuse or neglect increases the risk of that individual developing a personality disorder in adulthood.

How Are Personality Disorders Treated?

Because personality disorders can be so deeply ingrained and so longstanding, they are among the most difficult conditions to treat. People with personality disorders often resist change. Although some treatment methods can be effective, change may be slow. Treatment for personality disorders usually involves long-term talk therapy aimed at helping people understand how their particular pattern causes them trouble and then learning new ways to approach and solve specific problems. Medications are sometimes used to help treat mood disorders that may be associated with the personality disorder, such as depression or anxiety.

See also Antisocial Personality Disorder • Anxiety and Anxiety Disorders: Overview • Child Abuse • Delusions, Delusional Disorders, and Paranoia • Depressive Disorders: Overview • Obessive-Compulsive Disorder • Psychopharmacology


Books and Articles

Fox, Daniel. The Clinician's Guide to the Diagnosis and Treatment of Personality Disorders. Eau Claire, WI: PESI Publishing & Media, 2013.

Millon, Theodore. Disorders of Personality: Introducing a DSM/ICD Spectrum from Normal to Abnormal. Hoboken, NJ: Wiley, 2011.


Grohol, John M. “Personality Disorders.” . (accessed March 19, 2016).

MedlinePlus. “Personality Disorders.” U.S. National Library of Medicine, National Institutes of Health. (accessed November 11, 2015).

Merck Manual, Consumer Version. “Personality Disorders.” (accessed August 8, 2016).

National Institute of Mental Health. “Borderline Personality Disorder.” National Institute of Mental Health, (accessed March 19, 2016).


American Psychiatric Association. 1000 Wilson Blvd., Suite 1825, Arlington, VA 22209-3901. Telephone: 703-907-7300. Website: (accessed March 19, 2016).

Mental Health America. 2000 N. Beauregard St., 6th Floor, Alexandria, VA 22311. Toll-free: 800-969-6642. Website: (accessed March 19, 2016).

National Alliance on Mental Health. 3803 N. Fairfax Drive, Suite 100 Arlington, VA 22203. Telephone: 703-524-7600. Website: (accessed March 19, 2016).

National Institute of Mental Health. Science Writing, Press, and Dissemination Branch, 6001 Executive Blvd., Room 6200, MSC 9663, Bethesda, MD 20892. Toll-free: 866-615-6464. Website: (accessed March 19, 2016).

* psychologists (sy-KOL-o-jists) are mental health professionals who treat mental and behavioral disorders with support and insight to encourage healthy behavior patterns and personality growth. Psychologists also study the brain, behavior, emotions, and learning.

* inborn means present from birth or inherited.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)