Abstract
It has long been argued that surgery is a form of psychological stress and that the response to it should therefore be modifiable by psychological means. In particular, it has been suggested that preoperative worry should reduce the stressfulness of surgery. Endocrine responses to surgery may enable a more valid test of this theory than the measures more commonly used. A series of studies has provided evidence consistent with the theory. Preoperative anxiety correlated with lower postoperative levels of circulating cortisol and adrenaline. Furthermore, preoperative psychological procedures designed to reassure patients and reduce anxiety have increased cortisol or adrenaline responses. Programmes of preoperative reassurance should be evaluated carefully until it is known whether the increased stress response compromises recovery.