MONDAY, Nov. 21, 2005 (HealthDay News) -- "Nurture" may indeed be able to create a hormonal impact on "nature."
A study of adopted orphans suggests early emotional deprivation can lead to hormonal deficiencies. This, in turn, may undermine an individual's ability to form healthy relationships as he or she ages.
Focusing on children raised in harsh orphanage environments in Russia and Romania prior to adoption by American families, researchers observed significant long-term drops in two hormones known to be key to regulating emotion.
"Previously, we haven't known very much about how the early social experiences we have in infancy may play an important role in later life, and this suggests that the kinds of social experiences we have in infancy really are important in configuring the human brain and influencing the social behaviors we exhibit as adults," said study co-author Seth D. Pollak from the department of psychology at the University of Wisconsin in Madison.
The hormones in question -- oxytocin and arginine vasopressin (AVP) -- are believed to play an integral role from birth onward in priming children to communicate and bond with their parents, peers and other adults.
The absence of such a hormonal "safety blanket" may explain some behavioral problems displayed later in life by kids initially exposed to poor caregiving, the researchers conclude.
Pollak and his colleagues compared the hormonal levels of 18 children raised in orphanages shortly after birth with those of 21 children reared by their biological parents.
Reporting in this week's issue of the Proceedings of the National Academy of Sciences, the authors describe the orphanages as settings where a "prominent lack of emotional and physical contact from caregivers" was the norm.
The children lived in these types of institutional environments for an average of about 17 months (ranging from seven to 42 months). At the time of the study, the children had been living with their adoptive families in the United States for an average of just under three years.
Both groups of children in the study were of comparable age and physically healthy. The biological and adoptive families all lived in the Wisconsin area and shared similar well-to-do socioeconomic profiles.
Over the course of a two-week period, all the children were exposed to an interactive computer game while sitting for a half hour in the lap of both their mother and, subsequently, an adult female stranger.
Throughout each game session, the adults engaged with the children by means of tickling, patting, counting, and whispering. Prior to, and within 20 minutes of the interaction, researchers obtained urine samples to track changes in hormonal levels.
The researchers found that while the amount of oxytocin among the children did not differ before the experiment, AVP levels were lower among those who had been raised in the orphanage environments.
In addition, the orphans didn't experience the rise in oxytocin hormones seen in family-reared children following game sessions involving their mothers.
But when the experiment was conducted with an adult the child didn't know, no differences in oxytocin levels were observed. AVP levels were comparable for both groups of children following sessions with either the mother or the adult stranger.
According to the researchers, the observed differences in hormonal activity between the two groups of children points to developmental changes in the brains of the adopted orphans. Specifically, neurological mechanisms directing the activity of oxytocin and AVP may have been altered in children deprived of stable and nurturing family environments, they said.
Pollak said further research is need to clarify the long-term effects of early neglect and to point to treatments, including medication, that might help these at-risk children.
"One of the most interesting things is that a lot of parents who've adopted children from these orphanages often talk about the children being anxious -- having temper tantrums, being nervous kids, having trouble dropping them off at school," noted Pollak. "So it may be a biological mechanism that is not operating well that explains this."
Dr. Bruce Perry, a senior fellow at the Houston-based nonprofit Child Trauma Academy, said the findings don't apply to adopted children in general, since most will have received adequate care from birth. And he said that, even for neglected children, behavioral problems aren't irreversible.
"We fully expect that when children who are neglected like this get care over time those parts of the brain affected are capable of changing, because the brain is malleable and capable of responding to a whole range of environmental experiences, both good and bad," he said. "So now these children are in a position where we can be hopeful that they will get better."
The National Institute On Drug Abuse has information about early childhood trauma and drug use later in life. .