The Composite International Diagnostic Interview (CIDI), the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and the International Personality Disorder Examination (IPDE) constitute part of a family of instruments which have been designed for the assessment of mental disorders as defined by the explicit diagnostic criteria and algorithms in ICD 10 and DSM III-R. They have been developed at the request of the World Health Organization and the United States Alcohol, Drug Abuse, and Mental Health Administration to foster a common language in the mental health field, to facilitate comparisons of clinical and research findings from different settings, countries and cultures, and to improve the scientific basis of diagnosis and classification in psychiatry. This report describes the background, purpose and essential features of the three instruments.

The systems or lists that make up diagnostic criteria proposed by both classical and modern authors, as well as the usual national or international classifications constitute diagnostic instruments which allow: 1), classification of patients into the most homogeneous groups possible, according to absent-present criteria; 2), research on the propensity for certain criteria to appear, and on their stability; 3), a polydiagnostic approach, not limited to any one reference diagnostic system; 4), a group of psychiatrists to establish the capacity to construct empirical criteria for diagnosis and diagnostic-differential criteria of one or several nosological entities. If this group of psychiatrists is notably representative of a certain country or set of countries, these criteria allow for means of validation of the very empirical criteria established, as well as of the systems and classifications that integrate the instrument used, with their points of agreement and disagreement; 5), the establishment of a correspondence between empirical criteria and conceptual criteria, with predictions as to the application and way of using a new classification or of proposed projects, from the overall perspective of an empirical-conceptual relationship.

Several reviews on social functioning measurements using structured interviews or questionnaires have been published in recent years. This report examines Weissman and Brugha’s report on these tools and the respective interest of self-rating scales or interviews. In the elderly, multidimensional tools such as MAI or CARE have proven to be very useful. Questionnaires may be the best tools for assessing social adaptation in the elderly: a short self-rating scale that aims to assess social adaptation in the elderly in the community has therefore been presented. The SII Q is derived from the Multilevel Assessment Instrument (MAI) and the Index of Social Support (ISS). A principal component analysis of this new Social Integration and Independence Questionnaire (17 items) elicited four factors accounting for 48.8% of the variance, representing four parameters of social functioning: independence, social integration, familial interaction and depression.

The algorithms for the demonstration of shared phenomenology of psychiatric syndromes in DSM-III are resistant to quantification. In contrast, the rating scale approach quantifies clinical target syndromes in psychiatry. The two most useful statistical models for quantifying shared phenomenology by symptom rating scales have been reviewed; namely factor analysis and latent structure analysis. Results have shown that factor analysis has demonstrated dimensions of dementia, delirium, schizophrenia, mania, outward aggression, depression and anxiety. Latent structure analysis has confirmed that the items of brief rating scales (such as the Melancholia Scale) are additively related implying that their total scores are sufficient statistics for the measurement of these factors or dimensions. Latent structure analysis should be considered as a psychometric “glasnost” compared to algorithm-resistant logic of quantification in DSM-III.

The authors present an overview of the process for developing DSM IV which has been characterized by extensive international communication and collaboration and which includes three stages of empirical review: systematic literature reviews, analysis of unpublished data and field trials. Next, they describe in detail recently initiated DSM IV field trials. The field trials will study eleven diagnostic categories which continue to be the focus of much discussion. They include antisocial personality disorder, autism, disruptive disorders, dysthymia, insomnia, mixed anxiety and depression, obsessive-compulsive disorder, posttraumatic stress disorder, schizophrenia, somatoform disorder and substance use disorders. Each field trial compares the DSM III, the DSM III-R, ICD 10 and proposed DSM IV criteria for the disorder in question.

The chapter dealing with the classification of mental disorders in the Tenth Revision of the International Classification of Diseases (ICD-10) has been developed after consultation with experts in many countries. Each of the categories has been clearly defined so as to facilitate the assignment of diagnoses. The descriptions of categories and the diagnostic guidelines have then been tested in 110 centres located in over 40 countries, and the results have been used to finalize the text. The classification will be issued in several versions - one for statistical purposes, one for clinicians, one for researchers and one for general practitioners. A multiaxial presentation of the classification is being tested at present and will be made available in early 1993. The paper describes the requirements and principles which led to the classification, depicts the process outlined above and gives prospects for the future.

Clinical psychiatrists face the dilemma of ‘humanism’ versus ‘reductionism’ when confronting the problem of diagnosing and classifying patients. The introduction of ‘operational’ or ‘explicit’ diagnostic criteria (ODC) should provide a middle-ground enabling the clinician to combine person-oriented approach with a more rigorous application of knowledge-based decision rules. More than a decade of world-wide experience with ODC should enable at least a preliminary evaluation of their utility and cost not only from the point of view of the clinician and researcher but also from the position of mental health care consumers. In order to maximize usefulness, the developpers and users of ODC should avoid their ‘reification’ as the ultimate standard in psychiatric diagnosis and retain an attitude of epistemological openness.