The ICD is the World Health Organization's international system for classifying and coding health conditions, including the diagnostic descriptions for ADHD and autism.
The current version, ICD-11, came into effect on 1 January 2022. In ICD-11, ADHD and autism spectrum disorder are listed in the neurodevelopmental disorders section, alongside disorders of intellectual development and developmental learning disorders.
ICD-11 describes conditions in words and relies more on clinical judgement than the DSM's numbered criteria do. Its autism description also records whether intellectual development and functional language are affected.
Clinicians in Ireland and the UK use the ICD alongside DSM-5-TR. A diagnosis in a report may include a diagnostic code from the ICD, which health records use.