Narcissistic personality disorder (NPD) is a personality disorder with a long-term pattern of abnormal behavior characterized by exaggerated feelings of self-importance, excessive need for admiration, and a lack of empathy. Those affected often spend much time thinking about achieving power or success, or on their appearance. They often take advantage of the people around them. The behavior typically begins by early adulthood, and occurs across a variety of social situations.
The cause of narcissistic personality disorder is unknown. It is a personality disorder classified within cluster B by the Diagnostic and Statistical Manual of Mental Disorders (DSM). Diagnosis is made by a healthcare professional interviewing the person in question. The condition needs to be differentiated from mania and substance use disorder.
Treatments have not been well studied. Therapy is often difficult, as people with the disorder frequently do not consider themselves to have a problem. About one percent of people are believed to be affected at some point in their life. It appears to occur more often in males than females and affects young people more than older people. The personality was first described in 1925 by Robert Waelder, and the term NPD came into use in 1968.