Abstract
Field trials of the “Mental and Behavioural Disorders” section of the 1987 draft of the ICD-10 have been co-ordinated for the World Health Organisation by a number of regional centres. The design of the field trials and the major features of ICD-10 are briefly discussed. The results of the field trials in the Western Pacific region are described, and compared with the results of the original DSM-Ill field trials. ICD-10 appears to be an acceptably reliable diagnostic system, and the ratings of its feasibility and utility by participating clinicians suggest that it will be seen as a distinct advance over ICD-9.