The medical model has been the predominant approach used by physicians in diagnosing and management of diseases and illness in most Western countries. The biomedical model of illness and healing focuses on purely biological factors, and excludes psychological, environmental, and social influences. According to this model, good health is the freedom from pain, disease, or defect. It focuses on physical processes that affect health, such as the biochemistry, physiology, and pathology of a condition. It does not account for social or psychological factors that could have a role in the illness. In this model, each illness has one underlying cause, and once that cause is removed, the patient will be healthy again, (Alloy, Jaconson,& Acocella,(1999).
The bio-psychosocial model of understanding disease process arose from the context of changing conceptualisations of mind and body and the emergence of new fields of enquiry, including health psychology, medical sociology, behavioural medicine and psychoneuroimmunology, Barlow,D.H. & Durand V.M.(1999).
According to Engel (1977, 1980), human beings are complex systems and illness can be caused by a multitude of factors, not just a single factor such as a virus or bacteria. This is an attempts to move away from a simple linear model of health, to assess the effects of the combination of factors involved in illness, that is; biological (for example, virus & genes), psychological (for example, stress, behaviours, & beliefs) and social/environmental (for example, employment & neighbourhood). Engel (1977) argued that the best and most effective way of dealing with disease and illness is by the application of the three approaches that are related to human health. According to him the three interact in a very complex way and all play a significant role in human functioning in the context of disease and illness. Health is therefore better understood and managed when the three approaches are combined rather than handling it from a purely biomedical perspective.
The biopsychosocial model of understanding diseases and illnesses is also similar to the World Health Organization’s definition of health ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’ (WHO, 1946).
The biological model was the leading approach of understanding diseases and illnesses since the 19th century. It gained strength from researches in physiology and medicine that led in identification of infectious agents that cause diseases,(Maher & Maher,1985). It evolved from a Greek physician Galen’s germ theory concept of pathogens in 200 AD. He declared pathogens as the sole disease causing agents. The medical model therefore aimed at doing researches to identify all pathogens that caused diseases for the purpose of providing the right diagnoses for different diseases. For the proponents of this model, every illness is a symptom of a particular disease which has also been caused by a particular pathogen. The model also later focused on normalizing genetic related abnormalities and injuries. The model therefore focused on the physical processes such as the pathology, the biochemistry and physiology of disease and illnesses (Hoeksema, 2001). The biomedical model uses the traditional reductionist biomedical model of medicine that presumes that every disease process can be explained in terms of an underlying deviation from the normal function such as a pathogen, genetic or developmental abnormality or injury,(Sarno:1998). This argument presumes that illness is always due to abnormalities in the body's working systems. It is the basis of modern Western medical practice. It works on the theory that every bodily malfunction has an identifiable and diagnosable physiological cause that can also be managed or treated using the conventional medicine. The...