Psychological treatment for personality disorders

There is encouraging evidence that some patients with personality disorder are treatable. Psychotherapeutic interventions show promise, although interpretation of the literature is problematic: the number of patients in most trials is small, outcome measures are questionable, follow-up is limited, and treatments are multifaceted, complex interventions in which the effective components are unclear. The evidence base can be assessed according to efficacy and generalisability, and when both are taken into account the best verification is for psychodynamic therapy. However, there is inadequate evidence to make specific recommendations for any particular therapy. Anthony Bateman is Clinical Head and Research Lead of Psychotherapy Services at the Halliwick Unit, St Ann’s Hospital (St Ann’s Road, London N15 3TH, UK. Tel: 020 8442 6093, fax: 020 8442 6545, e-mail: [email protected]) and Visiting Professor at University College London. His interests include treatment of personality disorder and the integration of psychotherapy and psychiatry. Professor Peter Tyrer is Head of the Department of Psychological Medicine at Imperial College, London, honorary consultant in rehabilitation psychiatry, Central North West London Mental Health NHS Trust and consultant to an assertive outreach team in Hammersmith and Fulham. He has been interested in personality disorders since 1965. He is the Editor of the British Journal of Psychiatry, Past President of the European Branch of the International Society for the Study of Personality Disorders, Co-chair of the Section of Personality Disorders of the World Psychiatric Association and the Founder President of the British and Irish Group for the Study of Personality Disorders. Psychological treatment for personality disorders 379 Advances in Psychiatric Treatment (2004), vol. 10. http://apt.rcpsych.org/ and it is commonly described as the difference between an explanatory trial, i.e. a trial in which treatments are compared under ideal (experimentally manipulated) conditions, and a pragmatic trial, in which the study is carried out under the conditions normally appertaining to ordinary practice. In the latter trial, possible confounders to the intervention may be present, and although they could be removed, to do so would create an artificial environment that would not allow the results to be transferred to ordinary practice. Schwarz & Lellouch (1967) showed that the results of explanatory and pragmatic trials could be very different even though the treatments under test were the same. As personality disorders commonly occur in conjunction with other disorders, there is a place for both in their evaluation. In evidence-based psychiatry these are sometimes described as trials of efficacy (explanatory) and effectiveness (pragmatic). Each has its advantages and disadvantages, but in general it is common to establish efficacy first under controlled conditions, before testing an intervention in conditions of ordinary practice. Because of the formidable difficulties of meeting these requirements (Box 1), there has been a tendency for investigators to abandon them or at least to fulfil them only partially, and the literature on personality disorder, particularly with psychotherapeutic interventions, is often difficult to interpret (Bateman & Fonagy, 2000). Choice of outcome measures Outcome measures have always been a problem in psychiatric disorders, but these difficulties become even more pronounced in the case of personality disorders because there are no agreed common outcomes. The wide range of those that have been measured are summarised in Table 2. Personality disorders affect both the individual and society, and a range of outcomes can be measured to cover all these possibilities. Forensic psychiatrists and the general public may consider the effect on society to be the most important measure and insist that outcome for mentally disordered offenders is best measured by the frequency of re-offending. This is an easily measured, reliable statistic, although subject to social and judicial variation over time and distorted by a range of other factors such as the fact that patients who spend a long time in hospital or prison are not likely to reoffend. However, it does not record either symptomatic or personality changes, which are equally important, although they too may be subject to distortion. Changes in symptoms may be a consequence of change in mental state disorders quite independent of personality. In general, the interaction between personality disorder and Axis I disorder could result potentially in either an exaggeration of or an obscuring of a genuine treatment effect. Treatment might improve the mental illness but not the personality dysfunction or vice versa, and improvement in one may follow improvement in the other. Conversely, it is well known that mental illness can create the impression of abnormal personality, but that these characteristics change as the mental illness improves. Thus, any measured change in personality should be regarded in the first Table 1 Summary of treatments used for personality disorder and the level at which they have been investigated Type of treatment Main purpose of treatment Evidence level 1 Psychodynamic therapy To increase reflective capacity and emotional and interpersonal understanding 1 Cognitive–behavioural therapy To alter dysfunctional core beliefs 1 Dialectical behaviour therapy Initially, to reduce self-harm; eventually, to achieve transcendence 1 Therapeutic community To effect attitudinal and behavioural change 2 Cognitive analytic therapy To achieve greater self-understanding 3 Behaviour therapy To improve maladaptive behaviour 3 Nidotherapy To achieve better environmental adjustment, thus minimising impact of disorder (Tyrer, 2002a) 4 1. Using a scale of 1 to 5 (1, randomised controlled trial; 5, expert opinion). Box 1 Requirements for establishing an