Understanding Depression: Beyond the Biomedical Model

Introduction A literature review of the evidence regarding aetiology, classification, epidemiology and treatment of depressive disorders was conducted. All of the domains that constitute the biopychosocial model were investigated as a basis for testing the hypothesis that a biomedical approach, or any domain in isolation, is inadequate for fully understanding depression. An integrative, explanatory, conceptual model was developed, based on supportive evidence that can better inform the clinical encounter. Methods A combination of manual and electronic searches were conducted. Medline, Psychlit, Sociofile and the Social Science index databases were accessed with multiple key words. The University of Queensland library catalogue was also searched. Part A - Historical and Philosophical Basis The limitations and challenges of the biomedical model are followed by suggested responses, in particular a biopsychosocial model applied within a patient-centred consultation style. Various methods of scientific enquiry are needed to develop a more complete understanding of depression. Part B - Assessing the Evidence Evidence from epidemiological, biological and psychosocial research is reviewed. Depressive illness tends to be a chronic or recurrent condition with multifactorial causation, and occurs on a complex spectrum of severity. There is emerging evidence for a chronic stress response being the initial biological dysfunction, This is consistent with the frequency of stressful life events that precipitate depressive episodes. There is convincing evidence for predisposing factors such as low self-esteem, poor interpersonal skills and deficiency of social support. A range of treatment modalities, for example pharmacotherapy and various psychotherapies, appear to have similar effectiveness, which suggests that recovery occurs when the perpetuating cycle is broken at different sites. Part C - Integrative Models. Available schematic integrative models are reviewed and most fall short of integrating the three domains of the biopsychosocial, or fail to illustrate the circular nature of causation. A model is proposed, based on the evidence reviewed in Part B, that addresses both considerations. Conclusion Some causal factors for depression are supported by evidence. Models that integrate these findings are necessary to more fully explain depression. When applied in conjunction with patient-centred consultation styles, improved clinical outcomes could be expected. There is the potential for further research to test out the benefit of such a biopsychosocial approach, and to better elucidate component causes and reversible risk factors. There is a need for narrative approaches to receive considerably greater attention