Until the late 20th century the medical model was dominant in explaining the development of chronic illnesses such as cardiovascular disease. However, in recent years it has become clear that such illnesses may involve a significant psychosocial dimension with emotional states and prevailing beliefs influencing physiological mechanisms and complex high risk behaviours such as poor diet and smoking habits. In this lecture, we will provide a critical overview of the research linking mental states (including psychiatric conditions) with physical disorders. From the works of Hippocrates to those of Heberden, Trousseau and Sir William Osler, we will consider the evidence linking emotion to cardiovascular disease and the cardiovascular reactivity hypothesis, together with recent research linking depression and coronary heart disease. We will then evaluate some of the research attempting to link certain cancers with psychological states, arguing that such studies are often methodologically flawed. This lecture should be interesting for anyone with a passing interest in the proposed relationship between mind and illness and will provide some pointers as how to distinguish effective from flawed research designs.