Blood biomarker could help break depression-inflammation cycle

Depression and inflammation are linked, but, like the chicken and the egg, it has never been clear which comes first—until now. Based on results from a study of volunteers, it finally seems that the depression might come first.

Researchers followed a group of children and adolescents into adulthood, monitoring their levels of C-reactive protein (CRP), a blood biomarker of inflammation, and any episodes of childhood depression.

According to the researchers, the levels of CRP did not predict depression but depression was associated with raised CRP levels (and therefore inflammation), suggesting that depression (or the causes of depression) could cause inflammation in the body. The more episodes of depression, the higher the levels of CRP.

"Our results support a pathway from childhood depression to increased levels of CRP, even after accounting for other health-related behaviors that are known to influence inflammation. We found no support for the pathway from CRP to increased risk for depression," said Dr. William Copeland of Duke University Medical Center.

By inciting inflammation through the body, it is possible that depression in childhood could lead to diseases linked with inflammation, such as heart disease and diabetes, in adulthood. Perhaps, by treating or managing children's depression, physicians could reduce disease in adults.

Still no news on the precedence of the egg or the chicken though. Sorry.

- read the abstract in Biological Psychiatry
- see the press release