Depression May Be Caused by Inflammation

What do heart attacks and depression have in common? Both might be caused by inflammation.

Inflammation is our immune system’s natural response to injuries, infections, or foreign compounds. When triggered, the body pumps various cells and proteins to the site through the blood stream, including cytokines, a class of proteins that facilitate intercellular communication. It also happens that people suffering from depression are loaded with cytokines.

depression
Depression may be triggered by an immune response.

Which has some scientists thinking that depression may be a side effect of inflammation. That knowledge alone could lead to new treatments for depression, but even more effective would be to discover what’s causing the inflammation in the first place. Here, researchers are split.

Some think the inflammatory response may be spurred by an infection of some kind. Others think obesity or modern high-trans-fat, high-sugar diets could be the cause. Still others say that stress from bullying, rejection, or loneliness may be to blame.

Whatever the ultimate cause, researchers have begun exploring treatments that tackle the inflammatory symptoms of depression rather than the neurological ones. Here’s Caroline Williams, reporting for the Guardian:

The good news is that the few clinical trials done so far have found that adding anti-inflammatory medicines to antidepressants not only improves symptoms, it also increases the proportion of people who respond to treatment, although more trials will be needed to confirm this. There is also some evidence that omega 3 and curcumin, an extract of the spice turmeric, might have similar effects. Both are available over the counter and might be worth a try, although as an add-on to any prescribed treatment – there’s definitely not enough evidence to use them as a replacement.

It may be some years before scientists are finally able to sort out what the exact source of the inflammation, and it’s possible that different people will be susceptible to different causes. If and when they do, we’ll might add depression to the growing list of ailments—from allergies to heart disease and Alzheimer’s—that are caused or affected by an immune response gone wrong.