‘Cardiac psychology’ and ‘behavioural cardiology’ are two new closely related sub-specialties in mental health and cardiology, respectively, informed by many hundreds of empirical studies conducted over nearly half a century. The fields have evolved with a unifying hypothesis that psychological and social variables, termed ‘psychosocial factors’, can affect the development and outcome from coronary heart disease (CHD), the leading cause of death and disability in the western world. Indeed, the recent case-control INTERHEART study of more than 15 152 cases and 14 820 controls in 52 countries reported that most risk factors for myocardial infarction (MI) have behavioural components that are modifiable, including cigarette smoking, regular physical activity, dietary lipids, abdominal obesity, daily consumption of fruits and vegetables and hypertension (Yusuf et al., 2004) (see also ‘Diet and health’, ‘Physical activity and health’, ‘Tobacco use’ and ‘Hypertension’). A second INTERHEART study of psychosocial factors with 11 119 patients and 13 648 controls from 262 centres around the world determined that stress at work, at home and with finances, as well as major adverse life events, also increased the risk of acute MI (Rosengren et al., 2004).

In the late 1950s, some of the earliest research linked the Type A behaviour pattern with increased risk of MI. Since then, depression, social isolation, anger, anxiety and job strain, among others, have attained some degree of empirical validity as CHD risk factors.