Can depression cause heart attacks?

Fibrosis and Fight-or-flight: Physiology Meets Psychology

Isolation and depression go hand in hand. See more mental disorder pictures.
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The human heart depends on one thing to function, and apologies to the romantics of the world -- it's not love. The heart needs to pump efficiently, plain and simple. Healthy hearts contract and expand like a rubber band. When the tissue of the heart stiffens up, it doesn't flex and pump blood like it should. This is called fibrosis. The University of Maryland School of Medicine performed a study on 880 adults and found that people who are depressed are more likely to suffer from fibrosis.

Something of a chain reaction is taking place here. A blood protein called C-reactive has been linked to inflammation of the heart and blood vessels. Inflammation increases the production of collagen, the fibrous protein that connects your skin, bones, tendons and muscles. The problem with collagen is that if you have too much of it, it stiffens the heart. The study showed that depressed adults have higher levels of C-reactive than folks who are happy-go-lucky.

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Another study has pinpointed a second protein that may help to explain the link between depression and heart attacks. This one is called tumor necrosis factor alpha (TNF-alpha), and it's a member of a happy little protein family called cytokines. The cytokines can be your friend or your enemy. They're manufactured by your white blood cells and stimulate the immune system to help to fight injury and infection. However, in doing so it also causes inflammation, which we've learned is bad for the heart. People that suffer heart failure typically have high levels of TNF-alpha. The study by Ohio State University found that depressed individuals have higher levels of this protein. Getting back to the chicken and the egg, researchers aren't sure if the depression is causing the inflammation that leads to the heart failure or if the heart failure causes the depression that leads to the inflammation. Got all that?

Here's where matters get worse. Depression, stress and anxiety go hand in hand. So much so that scientists have classified a Type-D personality -- short for distressed. We've all been depressed at one time or another and we can all probably agree that it takes a toll on the body. You can't eat and you can't sleep. Your blood pressure increases, your heartbeat may speed up and you could even see a rise in insulin and cholesterol levels -- all from stress and anxiety. When your stress levels are up, your heart is going to be working overtime because of your jacked-up stress hormones, like adrenaline and cortisol. This kind of reaction is normal if faced with danger -- it's called the fight-or-flight response and it's necessary to help us handle stress. But with fight-or-flight, there's a fall in stress levels once the threat is gone. With depression and anxiety, it's like constantly having your terror alert set to red -- not good for your heart.