Refining the type A hypothesis: emergence of the hostility complex.

Recent negative research findings have raised questions regarding the robustness of the Type A hypothesis. A growing body of evidence suggests that not all aspects of the global Type A behavior pattern are pathogenic, but only those concerned with hostility and anger. Biologic mechanisms responsible for increased risk of coronary disease in persons with high levels of hostility and anger appear to involve increased cardiovascular and neuroendocrine responses to behavioral challenge, and, possibly, inadequate parasympathetic antagonism of sympathetic nervous system effects. Future research should concentrate on further refining our understanding of the hostility complex and its pathophysiologic mechanisms.