Personality disorder is a type of mental health disorder that affects the way a person thinks, behaves, and relates to others. It is characterized by a pattern of inflexible and maladaptive personality traits that cause significant distress or impairment in social, occupational, or other areas of functioning. There are several types of personality disorders, including borderline personality disorder, narcissistic personality disorder, and antisocial personality disorder, among others. Treatment for personality disorders often involves therapy, medication, and support from family and friends.