Classification and diagnosis of depression

There is no general consensus how to classify and diagnose depressive disorders. The main reason is disagreement regarding etiology. This is reflected in the several theoretical models of depression which has been proposed. On the other hand, a reliable way of characterizing groups of patients that can be used by both clinicians and researchers, is necessary both for communication and progress of research. Facing this situation, the inclusion of etiological theories in classification of depression obviously would be an obstacle to the use of such a classification system by clinicians of various theoretical orientation at current. Thus, a classification system which describes the clinical features of the mental disorders comprehensively and at the lowest order of inference necessary to identify the disorder in a reliable way is needed. The third edition of the Diagnostic and Statistical Manual of Mental Disorder (DSM-III) represents such a classification system. By providing operational diagnostic criteria for each diagnosis, DSM-III represents a major achievement of classification in clinical psychiatry and research. This paper will present the classification of depression and the problem of differential diagnosis as outlined in DSM-III. Further, the validity of the DSM-III classification of depression will be discussed with reference to some recent research findings on biopsychosocial and treatment aspects of depressive disorders.