Abstract
The variable natural history and expression of most diseases has highlighted the need for a new medical model. The current reductionistic views of disease indicate that all disease should be treated at the physiological level as all disease is a disorder of cellular biology. This view, held by a majority of medical practitioners, has also been adopted by lay persons thus propagating the existing limited model. However, the apparent inadequacies of this model in explaining the diversity of reactions to the same underlying biogenic cause has prompted the search for a new medical model. The physiological correlates of psychological functioning have been heavily scrutinised in an effort to explain the observed individual differences in disease onset and progression. This body of research has produced an amorphous collection of concepts and measurement tools aiming to supplement the medical model. The research reported in this thesis is an attempt to bring together many of the strands of research in this area in a psychometrically valid measurement tool and produce a model of ill health which will add to the knowledge base of the area. The main focus of this work has been the development of an index which ascertains psychosocial factors predictive of poor health outcomes, which has subsequently been used to predict poor infections disease outcomes. It is hoped that the research provided here will facilitate the adoption of a more holistic outlook towards medical practise, and that eventually, continued work in this area will lead to the adoption of this holistic model by medical practitioners and lay persons alike.