Your Heart, Your Mind-The Link
People have been learning about the link between heart disease and depression
since the 1970s, when researchers showed a connection between stress and sudden
death. This led to the conclusion, in the 1980s, that major depressive disorder
was an independent risk factor for major cardiac events in people with coronary
Like the classic question of the chicken and the egg
As time goes on, researchers are beginning to believe that the cause and effect
of depression and heart disease may be even more intertwined than they had understood.
One simple theory is that people who are depressed are less likely to take
care of their health. They may not seek treatment for heart problems, and even
if they are prescribed medication, they may not take it as they should. They're
also more likely to drink more alcohol, to get less exercise and to smoke.
It's also been noted for quite a while now that depression can result after
a heart attack occurs. This really isn't surprising when you think about it.
A heart attack makes people worry about all kinds of things-whether they'll
ever have good health again, whether death is closer than they thought, etc.
But some researchers now believe that it goes deeper than these somewhat logical
conclusions. For example:
Depression itself, independent of a cardiac event, can cause low levels of
inflammation throughout the body. Over time, this inflammation can damage blood
vessels and arteries. The vessel walls become stiffer, and sometimes pieces
break off, forming blood clots that can cause heart attacks.
When you have a heart attack, your body releases molecules that trigger inflammation.
This is a sort of message to the body that there's been a serious event and
it's time to be quiet and rest. That period of needing to lay low and conserve
energy may trigger depression in some people.
Studies have shown that people who suffer from depression have increased levels
of some inflammatory chemicals, and that depressed people who have had heart
attacks have higher levels of inflammatory chemicals than heart attack patients
who are not depressed.
Higher levels of cortisol
People who have depression often produce high levels of the hormone cortisol,
which is related to stress. This is a hormone that's useful when danger strikes,
because it puts you on alert and increases your heart rate. But if cortisol
is constantly flowing through the body, in can cause high blood pressure, higher
levels of insulin, more fat in the abdomen and higher bad cholesterol. All of
these elements can damage the cardiovascular system.
Lower serotonin levels
Many people who suffer from depression have low levels of a neurotransmitter
called serotonin. There's an entire class of anti-depressant drugs that increase
the amount of serotonin for the brain. Researchers have been finding that low
serotonin levels seem to be related to a higher heart rate, which in turn can
increase blood pressure and increase the risk of heart disease. Studies of depressed
monkeys have shown reduced levels of serotonin in the brain in the areas that
control mood and heart rate. Over time, the monkeys with low serotonin are more
likely to develop atherosclerosis, or hardening of the arteries.
Additionally, when serotonin levels are low, your blood tends to be thicker,
and that makes it harder for your heart to pump. Studies are now ongoing to
determine whether serotonin-boosting drugs can help people who have cardiovascular
Underscoring the need for heart and mind care
If you or your loved ones suffer from depression, it's important to make sure
to asses the health of your heart. And if heart problems are already present,
pay attention to the mental health aspect.
It's not really surprising that depression and heart disease are linked. Think
of the expression "a heavy heart." Your heart feels heavy when you
feel sad, or when problems are weighing on you. This is something that's been
known for ages and ages. But now, with a deeper understanding of the heat-mind
connection, there are so many things that medicine can do about it.
Psychiatric News, 5 August 2005; Archives of Internal Medicine, 28 November 2005; American Journal of Psychiatry, November 2005, The National Institute for Mental Health;