There is a natural curiosity about why some people are healthier than others. One consistent theme is that dispositional variables or personality may predispose people to poor or good health. This idea can be traced back to the writings of ancient scholars such as Hippocrates and Galen who proposed that individual differences in the four humours could predict health outcomes. Galen, for example, warned that melancholic women compared with sanguine women had a higher risk for breast cancer (Van Heck, 1997).