deeply ingrained and enduring behaviour patterns, manifesting themselves as inflexible responses to a broad range of personal and social situations. They represent either extreme or significant deviations from the way the average individual in a given culture perceives, thinks, feels and particularly relates to others. Such behaviour patterns tend to be stable and to encompass multiple domains of behaviour and psychological functioning. They are frequently, but not always, associated with various degrees of subjective distress and problems in social functioning and performance.

behaviours or traits that are characteristic of the person's recent (past year) and long-term functioning (generally since adolescence or early adulthood). The constellation of behaviours or traits causes either significant impairment in social or occupational functioning or subjective distress. Behaviours or traits limited to episodes of illness are not considered in making a diagnosis of Personality Disorder.