The ICD-11 classification of mental, behavioural or neurodevelopmental disorders: evidence, innovation, and implementation

The ICD-11 is the first comprehensive revision of the ICD in 30 years, and incorporates major advances in scientific evidence, best clinical practices, and health information systems. The WHO Department of Mental Health and Substance Use has led the development of the Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders (CDDR), which provide the information needed by psychiatrists and other mental health professionals to reliably apply the ICD-11 classification of Mental, Behavioral or Neurodevelopmental Disorders in their work with patients.

This presentation will provide an overview of the ICD-11 mental disorders classification and the CDDR and their development and describe important innovations relative to ICD-10. An important innovation is the incorporation of dimensional approaches within a categorical system. New disorders have been added to the ICD-11, several of which have generated controversy, and a substantial number have been deleted. The Cartesian separation of “organic” and “non-organic” disorders has largely been eliminated. Importantly, ICD-10 gender identity disorders have been reformulated as gender incongruence of adolescence and adulthood and gender incongruence of childhood and are no longer considered mental disorders.

The transition to a new version of the ICD requires careful planning at the national and health system level to guarantee functionality, interoperability of systems, and quality of data. Early engagement in the transition, such as is occurring in Scotland, leads to improved identification of local needs and the opportunity to design change management approaches. National professional societies such as the Royal College of Psychiatrists will be fundamental in the development and implementation of country-specific transition and implementation plans for ICD-11, as well as in the training of the health care workforce.