A new study has pointed out the ill-effects of childhood stress on kids, who end up battling long-term health issues.
The researchers found that adolescents who as youngsters have experienced either physical abuse or time in an orphanage are likely to have impaired immune function.
"Even though these children's environments have changed, physiologically they're still responding to stress," said senior author Seth Pollak, a professor of psychology and pediatrics at UW-Madison.
That can affect their learning and their behavior, and having a compromised immune system is going to affect these children's health," Pollak added.
As director of the Child Emotion Laboratory in the UW-Madison Waisman Center, Pollak focuses on how experiences early in life affect children's subsequent development. In the current work, he and fellow Wisconsin psychology professor Chris Coe, an expert on the links between stress and immunity, turned to the immune system as a way to isolate the consequences of early events.
"The immune system is not preset at birth. The cells are there, but how they will develop and how well they'll be regulated is very much influenced by your early environment and the type of rearing you have," said said Wisconsin psychology professor Chris Coe.
In the study led by Elizabeth Shirtcliff of the University of New Orleans when she was a postdoctoral fellow at UW-Madison, the authors evaluated immune-system strength among adolescents who have had stressful experiences either typical or unusually stressful childhoods.
The researchers looked for high levels of antibodies against the common and usually latent herpes simplex virus type 1 (HSV-1).
"We can use the control of latent viruses as one way of assessing the competence of the immune system," Coe explains.
"During times of stress or if the immune system is not appropriately regulated, the herpes virus is more likely to reactivate," he added.
They found that adolescents with a history of physical abuse and stressful home environments had higher levels of HSV-1 antibodies, showing that their immune systems were compromised.
"That is very unfortunate, but it was not surprising," Pollak said, since stress is widely known to have negative impacts on immune function.
"It suggests that children's emotional environments are having widespread repercussions on their health," the researcher added.
Moreover, another group of adolescents in the study, who spent time in orphanages in Romania, Russia or China before being adopted by U.S. families, showed a similar impairment of immune regulation.
"These children began their lives in a stressful environment, but they're now adolescents, and for a decade, they've been living in stable, affluent, loving environments. And yet, their immune systems are compromised as well. In fact, they look just like the physically abused kids," said Pollak.
"The bottom line is that these early stressors can really have long-term implications," Pollak added.
The study appears online in the Proceedings of the National Academy of Sciences.