It would appear that the type A behavior pattern (TABP) is an independent risk factor for coronary artery disease (CAD), particularly at younger ages, and for incidence of initial myocardial infarction. Competitiveness may be the so-called 'toxic' factor in TABP, having seminal importance in aggressive drive, accelerated pace, impatience and hostility. Nevertheless, it seems unlikely that human emotional and behavioral aspects can ever satisfactorily be subdivided into single component parts such as 'hostility'.