A Chemical Marker of Child Neglect Is Detected

Scientists have found startling differences in a hormone linked to social bonding in children who spent their first years in some foreign orphanages. These changes remained two years after they went from an environment of neglect to one of love and attention.

The finding, published in the Proceedings of the National Academy of Sciences, suggests that early experience can leave a biochemical mark that can shape lifetime experience.

The hormone, oxytocin, has been called the peptide of love. It works on brain centers linked to reward and emotion.

In the study, lead author Seth Pollak and his colleagues recruited 21 children reared by their biological parents and 18 who had been adopted after spending their first two years in Romanian or Russian orphanages. Each of the orphans had been in adoptive homes for two years before the study began.

In the experiment, a child and mother sat in a chair playing a computer game designed to elicit a social bond.

Urine samples were taken before and after the experiment. The researchers took measurements of several hormones, including oxytocin and vasopressin, both linked to social bonding and comfort.

The experiment was repeated with a friendly young woman, albeit a stranger.

The researchers found that the oxytocin levels of the children being reared by their biological parents increased when they played the game with their mothers. The levels didn’t increase when they played the game with the stranger.

By contrast, all but three of the 18 adopted children showed no rise in oxytocin levels -- whether playing with their adoptive mom or the stranger.