Can Childhood Stress Inflame Later?

Depression and chronic inflammation later in life may have roots in childhood adversity

(RxWiki News) Stress can make people feel tired and depressed, but why? The body responds to emotional stress with inflammation just like it would with a physical injury.

A recent study looked at the inflammatory response to stress in adolescent girls and its relationship to depression. Results confirmed that early childhood stress could predict later inflammation and depression.

"Consult a therapist if your child experiences a lot of stress."

Gregory Miller, PhD, co-director of the Psychobiological Determinants of Health Laboratory at the University of British Columbia, and Steve Cole, PhD, professor of psychiatry at the University of California at Los Angeles School of Medicine, co-authored a study that looked at 147 healthy female adolescents with a stressful childhood. Every six months for 2.5 years, the girls were interviewed and had their blood drawn.

The blood was tested for two different inflammatory biomarkers, C-reactive protein (CRP) and interleukin-6 (IL-6). Stressful childhood status was determined based on whether or not the parents were separated, financial problems and family history of physical or mental illness.

Inflammation is a natural response to physical injury, such as with the swelling of a sprained ankle. Previous research suggested to the team that depression could result from the body’s inflammatory response to stress.

Based on the results from this study, the authors said, “Among subjects exposed to high childhood adversity, the transition to depression was accompanied by increases in both CRP and IL-6.”

Even 6 months after the depressive symptoms had gone away, the elevation of CRP remained. The results also demonstrated that elevated levels of IL-6 accurately predicted depression 6 months later.

The authors said, “This coupling of depression and inflammation was not apparent in subjects without childhood adversity.”

Dr. Miller said, “What’s important about this study is that it identifies a group of people who are prone to have depression and inflammation at the same time.”

“That group of people experienced major stress in childhood, often related to poverty, having a parent with a severe illness, or lasting separation from family. As a result, these individuals may experience depressions that are especially difficult to treat.”

The discovery that the CRP levels remained high 6 months after depressive symptoms had gone away is important to note in relation to chronic diseases.

Dr. Miller said, “Because chronic inflammation is involved in other health problems, like diabetes and heart disease, it also means they have greater-than-average risk for these problems.”

Further research will need to diversify beyond adolescent females to gain a greater understanding of the inflammatory response to stress, resulting depression and risk factors for disease.

Better understandings of the body’s response to stress and later outcomes could help to efficiently and effectively treat future illness. 

This study was published in the July issue of Biological Psychiatry. No financial information was given and no conflicts of interest were found.

Review Date: 
July 11, 2012