[Classification of mental diseases. From Bertillon to CID-10: a century of international collaboration]

The first International Classification of Diseases (ICD) was approved during the Congress of the Statistical International Institute, in Chicago, in Paris, in 1893. It was based on a list of diseases prepared by Jacques Bertillon. Minor changes were introduced in this classification during decennial revisions made at international meetings and it remained in use until 1948, when the World Health Organization's Provisional Committee was charged with the task of producing ICD-6. ICD-6 represented a major shift from the previous internal conceptualization, particularly in what concerns the Chapter V., dealing with mental disorders. From 1955 on WHO produced with approximately a 10-year interval ICV-7, 8, and 9. Few modifications in relation to ICD-6 were introduced by these revisions, except for the introduction of a glossary of terms in the chapter on mental disorders. This glossary had a major impact towards the development of a common language in psychiatry. Based on epidemiological findings, and based also on an intensive and extensive international network of clinicians and investigators, ICD-10 was published in 1992. It represented a substantial improvement regarding the conceptualization of the classification of mental disorders, in relation to previous revisions of the ICD. Future tasks relating to ICD-10 include training of health personnel for its proper utilization, in addition to finalizing further ICD-10 versions, e.g. for research purposes and for primary health care use.