Seminar 74 www.thelancet.com Vol 377 January 1, 2011 Lancet 2011; 377: 74–84 Department of Psychosomatics and Psychotherapy, University of Giessen, Germany (Prof F Leichsenring DSc, Prof J Kruse MD, Prof F Leweke MD); Department of Psychosomatic Medicine and Psychotherapy, University of Goettingen, Germany (Prof E Leibing DSc); Mental Illness Research, Education and Clinical Center, James J Peters VA Medical Center, Department of Veterans Affairs and Mount Sinai School of Medicine, New York, NY, USA (A S New MD) Correspondence to: Prof Falk Leichsenring, Department of Psychosomatics and Psychotherapy, University of Giessen, Ludwigstrasse 76, 35392 Giessen, Germany falk.leichsenring@psycho.med. uni-giessen.de Borderline personality disorder Falk Leichsenring, Eric Leibing, Johannes Kruse, Antonia S New, Frank Leweke Recent research findings have contributed to an improved understanding and treatment of borderline personality disorder. This disorder is characterised by severe functional impairments, a high risk of suicide, a negative effect on the course of depressive disorders, extensive use of treatment, and high costs to society. The course of this disorder is less stable than expected for personality disorders. The causes are not yet clear, but genetic factors and adverse life events seem to interact to lead to the disorder. Neurobiological research suggests that abnormalities in the frontolimbic networks are associated with many of the symptoms. Data for the effectiveness of pharmacotherapy vary and evidence is not yet robust. Specific forms of psychotherapy seem to be beneficial for at least some of the problems frequently reported in patients with borderline personality disorder. At present, there is no evidence to suggest that one specific form of psychotherapy is more effective than another. Further research is needed on the diagnosis, neurobiology, and treatment of borderline personality disorder. Introduction 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. 1–5 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 population 6,7 with a median prevalence of 1·35 as assessed by Torgersen and colleagues. 8 There is no evidence that borderline personality disorder is more common in women. 7,9 In clinical populations, borderline personality disorder is the most common personality disorder, with a prevalence of 10% of all psychiatric outpatients and between 15% and 25% of inpatients. 9,10 In a study of a non-clinical sample, 7 a high rate of borderline personality disorder was reported (5·9%), indicating that many individuals with this disorder do not seek psychiatric treatment. In primary care, the prevalence reported for borderline personality disorder was four-times higher than that in the general population, suggesting that individuals with this disorder are frequent users of general medical care. 11 Diagnosis According to the current psychiatric classification system in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), borderline personality disorder is characterised by a pervasive pattern of instability in interpersonal relationships, identity, impulsivity, and affect (panel). 12 For a diagnosis of borderline personality disorder, at least five of the nine criteria must be met. However, suicidal tendency or self-injury are the most useful indications for a correct diagnosis, 13 whereas suicidal tendency or self-injury and unstable relationships have been the most predictive features in follow-up studies. 14 Accordingly, the rank ordering of criteria as most prototypical of this disorder in DSM-IV was not supported by the evidence. Further research is needed to establish whether some criteria should be given more emphasis than others. 5 The nine DSM-IV criteria of borderline personality disorder seem to indicate a statistically coherent construct. 15 Because factor analyses have established both a one-factor model and a three- factor model (disturbed relatedness, behavioural dysregulation, affective dysregulation), an underlying multidimensional structure of borderline personality disorder consisting of three homogeneous components might exist. 5,15 With nine DSM-IV criteria and a threshold for five positive criteria of a diagnosis of borderline personality disorder, however, there are 151 theoretical possible ways of diagnosing this disorder. 2,3 Thus, despite conceptual coherence, borderline personality disorder seems to be a heterogeneous diagnostic Search strategy and selection criteria We searched Medline, PsycINFO, and Current Contents from their start dates to Dec 31, 2009, with the database-specific search terms such as “borderline personality disorder”, “borderline personality”, or “borderline disorder”. The search was updated in Aug 30, 2010. We mainly selected publications from the past 5 years. Studies had to meet criteria of recent Cochrane reviews on borderline personality disorder; 79,107 for example, participants had to be aged 18 years or older, diagnosis of borderline personality disorder was made by use of operational criteria such as that described by DSM-IV or comparable approaches (eg, revised diagnostic interview for borderlines); and outcome measures for which reliability has been indicated were used. In studies of psychotherapy, studies had to also report a clear purpose (eg, pre-defined therapeutic benefits), define a rationale for participant inclusion or exclusion, and include a detailed description of the intervention (eg, treatment manuals or manual-like guidelines). 79,107 Pharmacological interventions targeting cognitive-perceptual, affective, and impulsive-behavioural areas of borderline personality disorder were included. With respect to treatment, only randomised controlled trials (RCTs) were included. Two authors (FaL, FrL) independently extracted the necessary information from each article. In cases of disagreement, a third author was included (EL) and disagreements were resolved by consensus.