Diagnostic classification systems in psychiatry

For the last 30 years the 10th edition of the International Classification of Diseases (ICD-10) has aided clinicians in the UK in diagnosing mental disorders. Classification systems are important in ensuring a consistent approach to accurate diagnoses and a common language for communicating them. Such an approach to classification has further advantages in terms of influencing clinical decision making, research, and public policy. In 2022, the ICD-11 was published, including changes to the classification systems and diagnostic requirements for some disorders. Although the ICD has codes for many diseases, we aim to explain the changes in diagnostic criteria for psychiatric disorders in the new ICD-11 in a concise and primary care focused way.