Biopsychosocial model in depression revisited

There are two fundamental etiological perspectives about mental disorders; biomedical and psychosocial. The biopsychosocial model has claimed to integrate these two perspectives in a scientific way, signalling their interconnection and interdependence. To that end, it used a systemic conceptual framework, taking advantage of the possibilities which it offers to establish general principles for diverse systems, independently of their physical, biological or sociological nature. In recent years, drawing on the theory of systems, theories have been developing of the dynamic non-linear systems, applicable to networks of a large quantity of densely interconnected elements (also called complex systems), like the mind or the brain. We believe that this revised systemic conceptual framework can bring integrative ideas to apply to Depression, such as the "binding dysfunction" concept we use in this article. According to this, vulnerability or predisposition to Depression would be associated with the imbalance between activating and inhibiting interactions (between some cognitions and emotions at a mental level, and between certain neuronal groups at a cerebral level). Precipitating factors would imply the increase of the activation level over this pattern of cognitions and emotions, or over those neuronal systems. When stress goes beyond the vulnerability threshold an excessive positive feedback between cognitions and emotions would appear (and between groups of neurons) with insufficient inhibitory control to mitigate it, which would imply a mental/cerebral dissociation in dominions of different level of activation. As a consequence, the generation and dissolution of patterns of cerebral and mental activation will no Longer have the dynamism and flexibility that permits an optimal interaction with the environment ("binding dysfunction"). Therefore, our hypothesis is that the person with Depression will suffer at a cerebral level a functional dissociation in neural dominions (some rigidly hyperactive and others rigidly hypoactive) in determined locations, which would be a different combination from those found in other mental disorders. At a mental level, this would correlate with a functional dissociation in several cognitive-emotive dominions; some corresponds to over activated patterns of "depressive" cognitions and emotions that for that reason invade the consciousness frequently, intrusively and repetitively; meanwhile there are other alternative hypoactive emotions and cognitions that do not manage to become powerful enough to avoid the consequent distortion in the communication with the environment. (c) 2006 Elsevier Ltd. All rights reserved.