International Statistical Classification of Diseases and Related Health Problems (ICD) produced by WHO in the UK and used around the world. First edition 1893. Used by physicians, nurses, researchers, policy makers, patient organisations. Includes mental and physical disorders. ICD-10, 21 chapters, in Ch5, F30-39 are mood affective disorders, including bipolar and major depression, F20-29 are schizophrenia, schizotypal and delusional disorders