Understanding quality of life in medicine : a new approach

This article introduces the subjective side of quality of life as it has evolved within the discipline of psychology. Subjective well-being is also of special interest within medicine due to its links to pathology and the fact that it is managed by a homeostatic system. This form of management offers an explanation for the unusual properties of subjective well-being, including its normal positivity, stability, and nonlinear relationship to objective variables, such as physical health. Central to understanding is the proposition that subjective well-being mainly consists of a specific form of trait mood. This homeostatically protected mood has a genetic set point and it is the experience of this set-point mood that homeostasis is defending. The resources required to maintain normal homeostatic control are described. If these resources are inadequate to protect the experience of set-point mood, mood positivity falls, and there is a high probability of depression. In this article, the process of homeostasis is shown to assist understanding of intervention effectiveness within both psychology and medicine. This concerns matters of resilience, the nonlinear relationship between levels of subjective well-being, and the strength of challenging agents, and the important understanding that interventions designed to raise subjective well-being are critically dependent on its level at baseline. Key teaching points: • The physiological process of homeostasis has a parallel in psychology in the homeostatic management of subjective well-being. • Subjective well-being is a more globally informative construct than health-related quality of life. • How people feel about themselves and their lives cannot be simply predicted through measures of health. • When subjective well-being homeostasis is defeated, there is a high probability of depression.