Marilyn Elias, USA TODAY Tue Oct 11, 7:05 AM

By Marilyn Elias, USA TODAY Tue Oct 11, 7:05 AM ET

Infants ignored for long periods in foreign orphanages may miss the social interplay needed to "prime" brains for normal development, but adoptive parents say most kids who spend less than two years in an orphanage are mentally healthy, researchers reported Monday.

"The longer you live without a stable, supportive family, the more the risk for emotional and conduct problems," says University of Minnesota psychologist Megan Gunnar. She and neonatologist Dana Johnson are following about 2,300 children from other countries adopted by U.S. families in the 1990s. They spoke at the American Academy of Pediatrics meeting here.

PET scans show that the brain's emotional centers are already functioning in 1-week-old babies, says pediatric neurologist Harry Chugani of Children's Hospital of Michigan in Detroit. Those brain regions specialize in recognizing faces and picking up emotional cues.

Chugani also used scans to compare connective fibers in the brains of children never in orphanages with the brains of those adopted from Romanian orphanages where they received little attention. Adoptees from Romania had fewer fibers with weaker connections in their frontal cortexes, he says. The adopted kids are being treated for attachment problems, and he will re-scan them to see whether behavioral improvement changes their brains.

"It looks like the brain is wired for emotional bonding at birth," he says. "If that doesn't happen, the system goes awry."

Gunnar's study used a behavior problem checklist filled out by parents of kids adopted an average of six years earlier. Parents of children adopted before age 2 reported fewer emotional and behavior problems in their kids than reported by American parents overall.

But the adoptees were somewhat more likely than others to have trouble paying attention, according to parents. And the older the child when adopted, the greater the risk of problems, Gunnar says. Parents' views might differ from those of child development experts, she adds.

Johnson's study compared the children adopted internationally by married couples with those whose adoptive parents are single or living with a partner of either sex. The non-married received older kids who suffered more deprivation because married couples often get priority in adoptions, Johnson says. After taking into account how long kids were in institutions and quality of care, children cared for by the unmarried were just as well-adjusted as married couples' kids, he says.

Those most likely to suffer long-term problems were much shorter than average when adopted, probably a sign of deprivation. And they had sensory problems such as impaired hearing or sight, or being ultra-sensitive to touch or noises, Johnson says.

It's unknown how much genes or prenatal environment might influence recovery from early brain disturbance, Gunnar says. "Many of these kids have a remarkable capacity to turn around when they're adopted," she says. "The quality of the institutional care seems to matter most."