Inflammation is a way by which the body reacts to a physical injury. Now, researchers say that inflammation also occurs when a person experiences psychological trauma.

"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," Dr. Gregory Miller, one of the researchers said.

The researchers recruited a large number of women who were susceptible to depression. The researchers followed the study participants for over two years. During this time, researchers interviewed and collected blood samples from them at regular periods. They also assessed the level of childhood adversity.

Researchers checked for biomarkers in blood-C-reactive protein and interleukin-6 that show inflammation in the body.

Study results indicated that women who faced adversities during early childhood were more likely to be depressed and their blood samples showed an elevated level of inflammation biomarkers.

Participants who hadn't faced a troubled childhood had low levels of biomarkers for inflammation.

Researchers say that these people might be at higher risk of developing obesity, diabetes or heart diseases.

"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. They, along with their doctors, should keep an eye out for those problems," added Dr. Miller.

A related study says that children who are exposed to "adverse psychosocial experiences" tend to be at increased risk of developing diseases later in life. The immune system and metabolic system alters and these changes persist over time making these people prone to many diseases.

"This study provides important additional support for the notion that inflammation is an important and often under-appreciated factor that compromises resilience after major life stresses. It provides evidence that these inflammatory states persist for long periods of time and have important functional correlates," said Dr. John Krystal, Editor of Biological Psychiatry.