Inflammation Linked With Depression, Study Suggests

01/02/2013 12:41am ET | Updated January 23, 2014

Inflammation may be linked with depression and psychological distress, a new study suggests.

The study, published in the Archives of General Psychiatry and conducted by researchers at Herlev Hospital and Copenhagen University Hospital, found that people who have higher levels of C-reactive protein -- which is a sign of inflammation -- also have a higher risk of depression and distress.

C-reactive proteins are present in the blood. Levels of C-reactive protein go up when the body is experiencing inflammation; having a C-reactive protein level above 10 milligrams per liter of blood may be a sign of inflammatory disease, researchers explained.

The study included health information from 73,131 people between ages 20 and 100 who live in Denmark. Researchers found that the higher the C-reactive protein levels, the higher the odds of also being a user of antidepressants, being prescribed antidepressants, and being hospitalized because of depression.

The researchers noted that only an association was found -- not a cause-and-effect situation -- and that more research is needed to explain the association.

But still, the findings add to past research suggesting a potential link between inflammation and depression. Michigan State University researchers found that levels of a brain chemical called quinolinic acid, which is made from inflammation, are elevated in people who have severe depression and are suicidal, LiveScience reported.

For more on the possible inflammation-depression link, click over to this great explainer from Scientific American.