Seemingly healthy adults, if they were abused or neglected during childhood, have an elevated inflammatory response to stress compared to adults who had happier childhoods, says a new research.
Psychiatrists at Brown University and Butler Hospital led the research.
Lead author Linda Carpenter, associate professor of psychiatry and human behavior, said that prior research has revealed preliminary associations between inflammatory markers, (such as cytokines or proteins released in the bloodstream such as interleuken-6) and depression and anxiety disorders, so this new finding could ultimately improve doctors' understanding of how stressors in childhood shape the risk people face for developing those conditions later in life.
"Animal models have given us some signals about how the functioning of an organism's stress response system can run amok for the rest its life as a result of some of the earliest environment exposures - adverse ones in particular," said Carpenter, who also treats patients as chief of the mood disorders practice at Butler.
"This is one of a number of studies we've been doing with generally healthy adults, looking at the effects of adverse early environment and how it might create a biological abnormality that could predispose somebody to future depression or another medical disorders."
A study in 2006 at Emory University had shown that men who were mistreated as kids and were now struggling with symptoms of depression as adults had an elevated inflammatory response to stress, Carpenter said.
To conduct the research, the team recruited 69 adults, ranging in age from their late teens to early 60s. After administering a battery of tests to ensure that the subjects were psychiatrically healthy and not taking any medicines or drugs that would bias the results, the team surveyed them extensively about their childhood experiences. Of the group, 19 reported moderate to severe neglect or abuse.
To measure each group's inflammatory response to stress, the researchers then asked them to undergo a laboratory role-play called the Trier Social Stress Test, in which they had to appear before a panel of "judges" and both speak about their qualifications for their job and then count backward from a number by 13s. All the while, the researchers were measuring various vital signs and collecting blood samples.
Among the subjects who reported adverse childhood experiences, the concentrations of interleukin-6 in their blood were always elevated above those of the control group, and the gap widened considerably as the subject recovered from the psychological stress during several hours after the role-play.
The research has been published online last week by the journal Neuropsychopharmacology.