MEDICAL MATTERS:Depression is as much physical as psychological - and is linked to heart disease
IN MY book Flagging the Problem, I emphasise the importance of considering depression as a multisystem illness - as much a physical as a psychological illness. It is worth discussing the crucial links between depression and coronary heart disease (CHD), which have been under the microscope for some time.
Patients with depression have a two- to four-fold increased risk of developing cardiovascular disease and similar risk of mortality after experiencing a cardiac event. It is also felt that symptoms of depression predict future coronary events for initially healthy individuals, as well as a poor prognosis for those who suffer from established CVD.
Studies in those hospitalised for major cardiac events (such as major heart attacks, unstable angina, bypass surgery and stents) have revealed that between 12 and 20 per cent of them demonstrate evidence of significant underlying depression. It is not regarded as a simple reaction to CHD, but rather a completely independent illness.
Other long-term studies have suggested that major depression can precede the appearance of CHD by many years, and some would even regard it as a "risk factor" just as important as cholesterol, diabetes and so on.
Of great concern is the prognosis for those who have had major cardiac events and who have significant, concomitant, underlying depression, as it is felt to be significantly poorer. The most likely reason for this is the increasing risk of cardiac arrhythmias causing sudden heart death.
But how could an illness, which at first glance seems to only "psychological", actually lead to an increase in both coronary heart morbidity and mortality? In my own book I detailed the major role of elevated levels of our stress hormone glucocortisol in this process, as it leads to our blood clotting platelets becoming more "sticky", increasing risks of thrombosis in our coronary arteries. But clearly with the information that depression can predate CHD, often by considerable periods, there must be other underlying mechanisms involved.
I am interested in, for example, the link between arrhythmias and depression, for the common denominator is the cell membrane. Depression seems to increase the excitability of the electrical conduction system in the heart, almost certainly acting at the level of the cell membrane. Smoking, poor diet and lack of exercise are all more common in depression and all increase the risk of CHD, but seem to be only part of the picture. There seems to be a greater risk of developing diabetes in depression, which also increases the risks of CHD.
Proinflammatory cytokines have been implicated in the pathogenesis of atherosclerosis and consequent cardiovascular disease. Depressed patients both with and without cardiovascular disease have been shown to have elevated plasma levels of these inflammatory markers; is there a link?
The key question is whether treatment with antidepressants or talk therapies, like CBT, can reduce the risk of future CHD. There seems to be no significant proof that they do, although the jury is still out, in particular on the former, due to their effects on both serotonin and glucocortisol, where many still feel they may reduce the risks. Part of the difficulty in assessing their role is the multifaceted nature of both illnesses.
This is why I am interested in Omega 3 fish oils. We know they reduce the inflammatory markers: platelet dysfunction, triglyceride fats and in particular the cardiac muscle excitability in CHD. They act at cell membrane level in both the neurons in the brain and in the heart. They are recommended by cardiologists as a useful addition to normal therapies prescribed following major cardiac events, and in some studies reduce the risks of sudden cardiac death by up to 50 per cent.
There is varying support for their role in the treatment of depression. I have personally found them to be of considerable help as part of a holistic package. I recommend doses of between 500 and 1,000mgs per day and that patients continue using them even when the bout of depression is over. My reasons are twofold: firstly, I feel they are crucial nutrients for normal brain/mood functioning, and secondly, I am extremely aware of their positive cardiac effects.
This is also why I am so insistent that, from day one, proper nutrition and exercise must lie at the heart of our approach to treating/preventing depression, and it is worth highlighting the increased risks of nicotine/ alcohol misuse, as both increase risks of CHD.
My final advice for those suffering from either illness is to become more aware of the links. If depressed, check your cardiac risk factors - and if just over a cardiac event and feeling down, look for help.
• Dr Harry Barry is the author of Flagging the Problem - A New Approach to Mental Healthand director of Aware