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Is type A behaviour a cause of coronary heart disease?

If claims that stress from work may cause coronary heart disease are true, then the medicolegal implications are serious. These claims may be derived from suggestions in the literature that factors in the environment can induce type A behaviour in individuals and thus increase an individual's risk of coronary heart disease. Type A behaviour has been described as the behaviour of an individual who is constantly struggling to reach poorly defined goals, in the shortest time possible, and with the added elements of hostility and aggression. Two major prospective, non‐randomized studies which support this concept are examined and criticized. Another, the largest and most recent study that was both prospective and randomized (the Multiple Risk Factor Intervention Trial), did not confirm the results of studies which showed a higher incidence of myocardial infarction, recurrent infarction and mortality in patients with type A behaviour when compared with patients with type B behaviour. Methods of defining behavioural types are not consistent and there is no relationship between behavioural patterns, as defined by “type”, and the extent of coronary disease as defined by coronary angiography. Pathophysiological pathways that have been postulated between type A behaviour and coronary heart disease are discussed and it is concluded that there is no scientific proof of a link that has been established between them. Recent suggestions of other psychosocial causes of coronary heart disease include outwardly directed hostility and inwardly directed anger. A genetic determinant has also been suggested, wherein both type A behaviour and coronary heart disease have a common but parallel course. The inability to prove that type A behaviour causes coronary heart disease does not rule out the possibility that other psychosocial causes may be related to coronary artery disease.