A personality disorder is a type of mental disorder that causes a person to think, feel, and act differently than what is considered normal. These abnormal attitudes and behaviors are not likely to change and can cause the person problems in all areas of life, such as trouble getting along with others at work or in the home.
People with personality disorders may be described as manipulative or self-centered. They may lack empathy for others and have trouble following social norms. Personality disorders are lifelong and are often first noticed in early adulthood.
WebMD Medical Reference from Healthwise