Borderline personality disorder is a common mental disorder associated with high rates of suicide, severe functional impairment, high rates of comorbid mental disorders, intensive use of treatment, and high costs to society.1, 2, 3, 4 and 5 In recent years, research findings have contributed to an improved understanding and therapy of these difficult-to-treat patients. In this Seminar, we provide an up-to-date review of recent research on the diagnosis, epidemiology, course, causes, and treatment of borderline personality disorder in adults.
Epidemiology
In epidemiological studies of adults in the USA, prevalances for borderline personality disorder were between 0·5% and 5·9% in the general US population6 and 7 with a median