Anxiety and Fear-Related Disorders and Obsessive–Compulsive and Related Disorders

Anxiety and Fear-Related Disorders and Obsessive-Compulsive and Related Disorders are two new groupings in the Mental, Behavioural, or Neurodevelopmental Disorders chapter of ICD-11. This chapter reviews key aspects of the two new groupings and their component disorders, beginning with a discussion of debates about the ICD-11 meta-structure, and including a review of the nosological research on anxiety and obsessive-compulsive disorders that is the foundation for the choices made by ICD-11. Mental disorders differ from chemical elements in important ways, and so a psychiatric nosology should not try to mimic the Periodic Table; indeed, ICD-11 takes a conceptual approach that acknowledges the fuzzy nature of mental disorders, and that foregrounds the fact that classification systems must be fit for purpose. ICD-11 represents an iterative advance in respect of Anxiety and Fear-Related Disorders and Obsessive-Compulsive Related Disorders that may lead to improved diagnostic practices, and so ultimately to better clinical interventions around the world.