A child's response to an interactive video game, complete with cuddles from mom, can be quite different depending on how they were raised.Creedit: Jeff Miller/University of Wisconsin-Madison

Children who were seriously neglected in infancy can carry a physiological burden for years, even after moving to a loving environment. A study of their hormonal responses shows that their brains are less equipped to trust and form social bonds than other children.

Scientists stress that the longer-term effects of neglect on children and their hormones remain unclear. But the results after a few years are significant.

"We don't want to reach the conclusion that this difference is permanent," says Seth Pollak, a developmental psychopathologist at the University of Wisconsin, Madison, who led the study. But he adds that the take-home message is that "children really need to be in families".

Orphan origins

Pollak and his team measured the levels of two key hormones in 18 children adopted from Russian and Romanian orphanages. These resource-poor orphanages, where one adult may care for up to 40 infants, do not make it easy for newborns to form normal social attachments, says Pollak. The children left these orphanages about two or three years before the study, and have been living with adoptive parents in the United States.

The children, averaging 4.5 years in age, were asked to complete a 30-minute computer game while sitting on the laps of their adoptive mothers. The game directed children to engage with their mothers by, for example, tickling them or patting them on the head. For comparison, the researchers gave the same task to 21 Midwestern children who had been reared by their biological parents.

The researchers measured levels of oxytocin and vasopressin in urine samples before and after the game. Oxytocin has been nicknamed the trust hormone, and is known to facilitate social bonding in humans. The brain naturally produces the compound, and churns it out in certain situations, such as when being given a hug. Vasopressin has been shown to help animals recognize one another and bond.

Trust games

Both groups of children showed similar levels of oxytocin before the game, but only the children who had been nurtured from birth experienced a spike in the hormone after being given motherly attention during the task. Baseline vasopressin levels were only half as high in the adopted children as they were in the control group. The findings appear in the Proceedings of the National Academy of Sciences¹.

The results suggest that neglect early in life can have lasting effects, interfering with the development of crucial hormone-regulation systems in the brain. But Pollak stresses that all children could grow to develop normal social responses with time.

Pollak speculates that it might be possible to help traumatized children to feel comfortable in their new homes more quickly by supplementing their hormonal responses. A recent study revealed that people given nasal sprays containing synthetic oxytocin were more likely to trust others with their money (see 'Trust in a bottle' ).

"What if that nasal spray could help?" Pollak asks. 

University of Wisconsin, Madison

• References

  1. Wismer-Fries A., Ziegler T., Kurian J., Jacoris S.& Pollak S. . Proc. Natl Acad. Sci., 102. 17237 - 17240 doi: 10.1073/pnas.0504767102 (2005). | PubMed |