Depression and physical illness

The importance of depression in the context of disease was highlighted by a recent Lancet article indicating that depression produced the greatest decrement in health status in comparison to common chronic diseases such as angina, arthritis, asthma, and diabetes; and individuals with depression co-morbid with these other conditions had the worst health of all (Moussavi et al., 2007). Consequently, Steptoe’s edited book, Depression and Physical Illness, is timely and deals with what is a key public health issue. With contributions from many of the key scholars in the field, this book provides an overview of the aetiology of depression, its relationship with major health conditions, and a critical discussion of the biological and behavioural mechanisms by which depression influences health.
Part one sets the scene by presenting critical discussions of the prevalence of major and minor depression in the medically ill, and the role of psychological and socio-demographic variables in the aetiology of depression. The initial chapter introduces the notion that variations in the definition and measurement of depression affect its observed prevalence, 15-61%, in the medically ill. Evidence that this is the most common psychopathology in the medically ill is presented with illustrations of the variation in incidence across different populations and settings, and the importance of diagnosis. Chapter two presents evidence of a causal role for socio-demographic and psychological factors, e.g. economic position and life events stress, in the development of depression. The complex and inter-related nature of the association between depression and such factors is highlighted.
Part two focuses on the relationship between depression and various health problems. For example, chapters three and four discuss the links between depression and coronary heart disease. First, the research evidence to date on prospective associations between depression and the aetiology of coronary heart disease is critically evaluated, and the likely bio-behavioural pathways are considered, although less attention is given to the possibility of reverse causation. Second, evidence that depression contributes to poorer prognosis in cardiac patients is discussed. At the end of chapter four, the limited success of treatments for depression in improving cardiac prognosis is highlighted, and an appeal is made for the identification of more effective therapies