International Classification of Diseases, ICD-11, chapter 6

Chapter 6 of ICD-11 sets out the World Health Organization classification of mental, behavioural and neurodevelopmental disorders. It defines each condition, groups related presentations, and supplies the diagnostic codes carried into health records, statistics and clinical correspondence across the United Kingdom and Europe. The World Health Assembly adopted ICD-11 in 2019, and the revision came into force in January 2022. A companion manual, the Clinical Descriptions and Diagnostic Requirements, followed in 2024 to set out how each category is applied.

Two departures from ICD-10 bear on trauma and character work. Complex post-traumatic stress disorder now stands as a category in its own right, adding disturbances in affect regulation, self-concept and relationships to the core post-traumatic syndrome. Personality disorder has been rebuilt: the former categorical subtypes give way to a rating of severity alongside prominent trait domains, so a formulation records the degree of impairment rather than assigning a fixed type. Both changes alter what a diagnosis names and how a case record reads.