A personality disorder is a type of mental disorder in which you have a rigid and unhealthy pattern of thinking, functioning and behaving. A person with a personality disorder has trouble perceiving and relating to situations and to people. This causes significant problems and limitations in relationships, social encounters, work and school.
In some cases, you may not realize that you have a personality disorder because your way of thinking and behaving seems natural to you. And you may blame others for the challenges you face.
Personality disorders usually begin in the teenage years or early adulthood. There are many types of personality disorders. Some types may become less obvious throughout middle age.