Personality consists of enduring patterns of thinking, feeling, behaving and relating that determine how a person interacts with their inner psychological world and outer environment. Personality disorders are defined as deeply ingrained and maladaptive patterns of behavior that persist through adulthood. They are classified in the WHO's ICD-10 as codes F60-F69. Many famous historical and fictional characters are believed to have exhibited traits associated with specific personality disorders such as narcissistic personality disorder, obsessive-compulsive personality disorder, and borderline personality disorder. Nursing interventions for patients with personality disorders focus on frequent observation, setting limits on acting out behaviors, exploring feelings, and preventing dependence on individual staff members.