WORLD SCIENCE

"Long before it's in the papers"
August 03, 2010

Childhood neglect changes brain chemistry, researchers find

Nov. 21, 2005
Special to World Science

Researchers say they have identified lasting changes in brain chemistry that result from childhood neglect. The research might lead to drug treatments that help undo these changes, they added.

Absence of a loving caregiver in the first years of life can sway the normal activity of two hormones that help form healthy social bonds and emotional intimacy, the scientists found in a study.

Psychologist Seth Pollak and doctoral student Alison Wismer Fries monitored hormone levels in children before and after they played a computer game that involved interaction with their mothers. (Courtesy of University of Wisconsin-Madison)

The work, by investigators at the University of Wisconsin-Madison, is reported online in the Nov. 21 issue of the research journal Proceedings of the National Academy of Sciences. 

The researchers worked with 18 four-year-old adoptees who had spent their first years in orphanages in Russia and Romania. These institutions are often overwhelmed with children, and unable to provide a loving upbringing to each, the researchers explained.

Even though the children now live in stable homes—for over three years, in some cases—they might still display some telltale behaviors that researchers associate with early neglect, the researchers said. One is an abnormal willingness to seek comfort from unfamiliar adults, even in the presence of the adopted parent. 

The scientists tracked the levels of two “social” hormones, called vasopressin and oxytocin, in the children through urine tests. 

The researchers said they immediately noticed that the children who experienced early neglect had markedly lower levels of vasopressin than non-adopted children. Researchers think vasopressin is essential for recognizing individuals in a familiar social environment. 

During the experiments, the children sat on the laps of either their mother or an unfamiliar woman and participated in an animated interactive computer game. 

The half-hour game directed the children to engage in various types of physical contact with the adult they were sitting with, such as whispering or tickling each other, and patting each other on the head. At the end of the game, they were asked to give a urine sample.

The researchers said that in family-reared children, oxytocin levels go up following physical contact with their mothers. But in the neglected group, the levels stayed the same. Because oxytocin is necessary for forming secure relationships, this might help explain why many neglected children have trouble doing so, the scientists said.

But the results don’t indicate that victims of early neglect are permanently barred from forming healthy relationships, the researchers said. “It's extremely important that people don't think this work implies that these children are somehow permanently delayed,” said Seth Pollak, senior author of the study.

“All we are saying is that in the case of some social problems, here is a window into understanding the biological basis for why they happen and how we might design treatments.” 

In the future, he said, and his colleagues hope to identify how particular factors, such as the duration or severity of childhood neglect, might influence types of child behavior. Another question worthy of exploration, the researchers added, is why hormone levels vary between children who have suffered similar neglect.

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