Progress Toward Achieving a Common Language in Psychiatry

In preparing for the 10th revision of the International Classification of Diseases (ICD-10), the Division of Mental Health of the World Health Organization organized an international field trial to help evaluate draft clinical descriptions and diagnostic guidelines that were produced to facilitate use of the chapter dealing with mental and behavioral disorders. These clinical guidelines were prepared in equivalent versions in most of the world's widely spoken languages. The field trial aimed to obtain data that would help in assessing whether the classification fits the diagnoses made in different countries, whether it is easy to use, and whether psychiatrists after a short period of familiarization with the classification can reach agreement about their diagnoses and classification. The field trial was carried out at 112 clinical centers in 39 countries by 711 clinicians who conducted 15,302 individual assessments. The trial included joint clinical assessments of patients and case history exercises. The results of the joint assessment part of the trial are reported here. Most clinicians reported that the draft document was easy to use and that the classification provided a good fit for the vast majority of the clinical conditions encountered. While interrater reliability was satisfactory for most categories, some (for example, those dealing with personality disorders) were somewhat difficult to use, and reliability of assignment for those was lower. The trial demonstrated that the ICD-10 chapter dealing with mental and behavioral disorders is on the whole suitable for general use. It provided valuable indications about changes needed for subsequent versions and demonstrated the feasibility of large-scale international research on classification and diagnosis in psychiatry.