Personality is the way of thinking, feeling and behaving that makes a person different from other people. An individual’s personality is influenced by experiences, environment (surroundings, life situations) and inherited characteristics. A person’s personality typically stays the same over time.

To be classified as a personality disorder, one’s way of thinking, feeling and behaving deviates from the expectations of the culture, causes distress or problems functioning, and lasts over time.¹ The pattern of experience and behavior usually begins by late adolescence or early adulthood and causes distress or problems in functioning. Without treatment, personality disorders can be long-lasting.