[A new strategy for the classification of mental disorders: an example of a multi-dimensional model for...

Present diagnostic classification systems stand in the way of a concurrence between events in our social lives and the biological substrates of common mental disorders. A two dimensional model is presented for common mental disorders, defined by symptoms of anxiety and depression. Although anxiety symptoms are often related to threat and depressive symptoms to loss, the two types of symptoms are not independent and often co-exist. The data from two independent studies with general practice patients in which a common standardized research interview was used were analyzed using latent trait modeling. The results obtained for the symptoms of anxiety and depression, as for the diagnoses (ICD-9 or DSM-III) confirm the robustness of this model. The strength of this conceptual model is based on its potential simultaneously to illustrate the relationship between biological and social determinants of these common symptoms. These two types of symptoms are related to the physiological reactions in response to punishment and reward. They also illustrate how certain events in our social environment are specifically associated with the constitution of anxiety and depression. Conversely, genetic vulnerability appears to be non-specific and may determine an increased overall likelihood to develop symptoms under stress, but the nature of those symptoms (anxiety or depression) depend on other factors. Moreover, other variables (i.e. personality, social relations) modify the effect of these relationships. Our knowledge of inter-relationships between common psychiatric symptoms and events from the social environment thus appears sound, and is likely to withstand future developments in biological psychiatry.