Personality refers to characteristics that make individuals unique, including how they think, feel, and behave. A personality disorder is a lasting pattern of inner experiences and behaviors that deviate from cultural norms and cause distress. There are three clusters of personality disorders - odd/eccentric, dramatic/emotional, and anxious/fearful. The document provides details on specific disorders within each cluster such as paranoid personality disorder, schizoid personality disorder, and obsessive-compulsive personality disorder. It describes symptoms, causes, and treatment approaches for several disorders.