Today the focus on health is, to a large extent, on prevention because it is acknowledged that many health problems are related to lifestyle. It is believed that if people can change their lifestyle, their general health will improve.  Many health psychologists are involved in research on how to prevent illness, as well as how to promote health and reduce health risks. The goal of health psychology is to find ways to help people to stay healthy as well as how to best treat health problems - for example, in relation to alcoholism, stress, and obesity.

For the majority of the twentieth century, academics were members of a medical school of thought today called biological reductionism. Biological reductionism is an approach to health and medicine characterized by the assertion that all disease is determined exclusively by physiological dysfunction. The goal of biological reductionists was to create clear categories of these bodily dysfunctions and thus to be able to accurately predict who will become ill and subsequently how to best treat the problem. However, some scientists would argue that such an objective is unrealistic and even that such an approach to health and disease is just plain wrong.

One of these people was George Engel, an American psychiatrist who in 1977 wrote an article titled The Need for a New Medical Model: A Challenge for Biomedicine. In this work, he argued that it was ill-advised to only explain illness in terms of physiological dysfunction of the individual. Instead, he proposed that health was influenced by many different systems, which in turn also interacted with and influenced each other. Together, these systems - biological, psychological and social - determined one’s health.  Engel’s approach became known as the biopsychosocial model. According to this model, none of these factors in isolation is sufficient to lead definitively to health or illness—it is the deep interrelation of all three components that leads to a given outcome.

Among the advantages of the biopsychosocial model (BPS) is that it looks at individuals holistically - as systems - rather than passive responders to biological destiny.  It believes that a person can take control of their health behaviour. The model also puts a focus on prevention with the goal of avoiding health problems - or at least postponing them - as a result of promoting positive behaviours such as a healthy diet, exercise and stress management. A growing amount of research suggests that it is the combination of health status, beliefs about health, and sociocultural barriers to accessing health care that influence the likelihood of an individual engaging in health-promoting behaviors.

There are some limitations of such a model. First, it is not always clear how and to what extent these factors interact.  When carrying out research on one aspect of the model, it is often not possible to isolate that variable from other factors. For example, when studying the cognitive origins of stress, one cannot control for physiological factors. As a result, the model's predictive validity is often questioned. Another limitation is simply its practical application.  Being able to diagnose or treat an individual patient with regard to biological, psychological and sociocultural considerations is both time and resource consuming.

In this unit, you will find several examples of how the biopsychosocial model can be used to explain health issues.  You should be able to explain one of those health issues from the lens of each of the approaches in order to demonstrate an understanding of the model.