Classifications in the field of mental health.

For the first time in the Ninth Revision of the International Classification of Diseases (ICD-9) the chapter on mental disorders contained short glossary definitions for each category. A number of changes in attitudes and policies at the international and national levels, particularly the reorientation of mental health programmes to include behavioural and psychosocial problems, came at an opportune time and had a positive influence on the development of proposals for the chapter on mental and behavioural disorders in the Tenth Revision (ICD-10). This in turn enabled WHO to undertaken an intensive and extensive assessment of international needs in the classification of mental disorders and, where the situation was not unequivocal, to organize field trials to provide the empirical data necessary for problem solution. The result is a series of compatible classifications of mental and behavioural disorders based on ICD-10. The first, produced mainly as a reference tool for statistical purposes, will be included in ICD-10 with short glossary definitions as was the case for ICD-9. Other versions will be published for practising clinicians (with enhanced glossary definitions followed by diagnostic guidelines) for research (with full definitions, diagnostic guidelines and diagnostic criteria); for use in the provision of services to the mentally ill; and for use in general health (primary) care. There will also be a multiaxial classification of mental disorders in children to identify the clinical syndrome, resulting disability and environmental factors. It is hoped that these versions tailored to the needs of different groups working in the field of mental health will result in further improvements in communications between those responsible for the provision of services and care.