Personality disorder across the life course.

The pervasive effect of personality disorder is often overlooked in clinical practice, both as an important moderator of mental state and physical disorders, and as a disorder that should be recognised and managed in its own right. Contemporary research has shown that maladaptive personality (when personality traits are extreme and associated with clinical distress or psychosocial impairment) is common, can be recognised early in life, evolves continuously across the lifespan, and is more plastic than previously believed. These new insights offer opportunities to intervene to support more adaptive development than before, and research shows that such intervention can be effective. Further research is needed to improve classification, assessment, and diagnosis of personality disorder across the lifespan; to understand the complex interplay between changes in personality traits and clinical presentation over time; and to promote more effective intervention at the earliest possible stage of the disorder than is done at present. Recognition of how personality disorder relates to age and developmental stage can improve care of all patients.