Fear, anger, and grief may precipitate myocardial ischemia and infarction. The prognosis of patients with inducible ischemia during mental stress is worse than in those without inducible ischemia. The sympathetic nervous system plays an important role in stress-associated changes in cardiovascular regulation and contributes to cardiovascular morbidity and mortality by inducing vasoconstriction and tachycardia, as well as arrhythmia. Hostility--previously termed type A personality--is often associated with sympathetic hyperreactivity to mental stress and carries an increased risk for atherosclerotic vascular disease. As endothelial dysfunction is an early manifestation of atherosclerosis, the impact of mental stress on endothelial function is also important. Acute mental stress induces prolonged endothelial dysfunction in healthy volunteers, which is prevented by selective endothelin A receptor antagonism. This represents an important link between mental stress and atherosclerotic vascular disease. In addition, patients with depression show hypercortisolemia, and changes in platelet function leading to a prothrombotic state. These findings help to explain the increased cardiovascular risk in patients with depression.