FRIDAY, Oct. 18, 2002 (HealthDayNews) -- There are many good reasons to seek treatment for depression, but trying to avoid heart disease may not be one of them.
Several studies have found a definite link between depression and cardiac disease. Now a new study suggests that people being treated successfully for depression have problems that can lead to cardiac dysfunction.
"We have shown that people who have got over their bad bout of depression nevertheless still exhibit the rather dry-sounding endothelial dysfunction," says study author Dr. Andrew Broadley, specialist registrar in cardiology at Torbay Hospital in Devon, U.K. A report on the finding appears in the November issue of the European journal Heart. He did the research while at the University of Wales College of Medicine.
In simple language, the arteries of people treated for depression were not found to expand normally when large amounts of blood were forced through them. "This failure to dilate in response to increased flow is associated with the development of coronary artery disease, which is the number one cause of angina and heart attacks," Broadley says.
There were 12 patients and 10 healthy people in the study. The 12 patients had been treated for depression and had remained stable on their normal medications for a minimum of three months. When blood was forced through the artery of the arm, the cells in the lining of the arteries of healthy subjects produced nitric oxide. This substance causes muscle layers to relax and the arteries to expand. This effect was much less noticeable in people being treated for depression.
What causes this abnormality is not known, Broadley says. While epithelial dysfunction may be due to the depression itself, its cause could also be a result of the antidepressants the subjects were taking, or even a combination of both, he says.
Dr. Philip Strike, a clinical research fellow at University College London, wrote the accompanying editorial in Heart. "The elevation of mood does not reverse the abnormality of endothelial function, suggesting that there may be some common underlying mechanism for the two abnormalities rather than abnormality of mood alone leading to endothelial dysfunction," he says.
The researchers suspected an abnormality would be found among treated depressed patients that would demonstrate a possible predisposition to heart disease, but the type of abnormality was not what they expected, Broadley says.
Impaired endothelial function "may not sound very exciting, but it is exactly the same abnormality that is found in smokers, those with high blood pressure, those with high cholesterol and those with diabetes -- all of which are conditions that predispose significantly to heart disease," he says. "It has even been suggested that the endothelial dysfunction is the common pathway by which all those things that are bad for the heart's arteries actually do their damage. As such, it is a plausible mechanism by which depression damages the heart."
Dr. Stephen E. Kimmel, an assistant professor of medicine and epidemiology at the University of Pennsylvania, says that the bottom line of this study is that "we're not sure endothelial function is the only mechanism that increases cardiac risk in depressed patients."
Kimmel said he would like to see research that compares endothelial function in depressed patients to those treated for depression to determine whose endothelial function is more severe. "Endothelial function may be worse in untreated depressed patients," he says.
There are still many unanswered questions, Broadley admits, and having endothelial dysfunction does not mean that someone is sure to develop heart disease. "Those with depression or recovering from depression should continue with their prescribed medication, do all the things that we all should do to look after our health and seek to adopt as positive a mental attitude as possible. They should not worry that they are inevitably going to develop heart disease as this simply isn't true."
What To Do
To find out more about heart disease and depression, go to the National Institute of Mental Health or the American Heart Association.
