Sadness, isolation and loneliness can cause heart attacks. In one study in San Francisco and another in Eastern Finland, of the 20,000 people observed for up to nine years, those who were lonely and socially isolated were two to three times more likely to die from heart disease and other causes than those who felt connected to others. These results were independent of other risk factors such as cholesterol levels and high blood pressure (Am J Epidemiol, 1979; 109: 186-204; Am J Epidemiol, 1988; 128: 370-80).
Depression after heart attack has also been recognized as having an influence on patients' survival rate. Its impact is at least equivalent to that of left ventricular dysfunction and a history of previous heart attack (JAMA, 1993; 270: 1819-25). Again, this effect has been shown to be independent of the severity of the patient's condition (JAMA, 1993; 270: 1819-25; Circulation, 1995; 91: 999-1005).Depressed patients experience physiological changes such as decreased heart rate variability (J Psychosom Res, 1988; 32: 159-64; Am J Cardiol, 1987; 59: 256-62). Studies also show that the hormone serotonin not only plays a major part in the development of depression but also influences the formation of blood clots (Pharmocol 1991; 17(suppl5): S6-S12).
The low cholesterol regimes which heart attack patients are often put on only exacerbate the problem. Men with low cholesterol levels are three times as likely to commit suicide (BMJ, 1996; 313: 664). Those with naturally low levels are most at risk, but those whose levels are lowered by drugs are still at double the risk.