Personality Disorder: From Evidence to Understanding By Peter Tyrer and Roger Mulder Cambridge University Press. 2022 £29.99 (pb). 172 pp. ISBN: 9781108948371

Psychiatrists

Every psychiatrist and mental health professional should read this concise, elegant and witty account of the ICD-11 classification of personality disorders. The authors tackle historical, epistemological and ontological critiques of the personality disorder concept and dismantle decades of well-intentioned classifications that appear not to have served the patient well. The authors engage with cultural and national patterns in character, and comorbidities with other mental illnesses. Evidence on treatment outcomes (which is reassuringly hopeful) is provided, along with criticism of diagnostic practices that claim stigma and ‘isms’ are reinforced by such labels and can harm patients.

ICD-11 disrupts previous classifications on the basis of extensive field trials. The major shift is away from categorical classification to one of difficulty in relationships, inadequate social skills and personality difficulty. ‘Personality disorder’, rather than ‘personality difficulty’, is persistent, and occurs in all situations or contexts; there is impaired social and occupational function and associations with harm to self or others. Once a personality disorder in terms of severity is confirmed, it can be further classified into domain traits, of which there are five: negative affectivity, detachment, dissociality, disinhibition and anankastia.

With care the authors dissect the justification for retaining one category, borderline disorders, owing to appeals from clinical leaders and groups, given the evidence base on what works is compelling. Indeed, clinicians will have to familiarise themselves with the new classifications and develop a body of evidence that tests their value to people with impaired personality function.

There are descriptions about how to assess personality using the new system, and four structured measures of outcome, assessment tools, are included in the appendices. The two areas that could be strengthened include the reference to race and ethnicity, albeit, this is my particular interest in clinical and research terms; and then cognitive analytic therapy appears to be misrepresented as lacking a manual or practical value. This incisive account offers much information in a relatively easy to read format. If there is one thing you should read on personality disorder, this is it.