Adolescents who were adopted as infants are significantly more likely to have a psychiatric disorder than those who were not adopted, a study released Monday has found.
The researchers -- emphasizing that most of the adoptees in the study were psychologically healthy and faring well -- the said that as a group those adolescents faced a greater risk for two psychiatric conditions: attention deficit-hyperactivity disorder and oppositional defiant disorder.
About 7 in 100 adolescents who were not adopted met the criteria for attention deficit-hyperactivity disorder, about half the rate for adopted adolescents, said lead author Margaret Keyes of the University of Minnesota.
Attention deficit-hyperactivity disorder interferes with a person's ability to concentrate, sit still and control impulsive behavior. Young people with oppositional defiant disorder are uncooperative and hostile toward authority figures in a way that seriously impairs their day-to-day functioning.
The study, published in the May issue of the Archives of Pediatrics & Adolescent Medicine, compared a random sample of 540 adolescents who were not adopted, all born in Minnesota, with a representative sample of adoptees placed by the three largest adoption agencies in Minnesota. Of the latter group, 514 were foreign adoptions and 178 were domestic.
Researchers performed psychiatric assessments on all subjects, whose ages ranged from 11 to 21. Parents, teachers and the adolescents also were interviewed.
The researchers had thought that adoptees born overseas would be at higher risk of psychiatric disorders than those born and placed in the U.S., but they found the reverse was true.
"Our hypothesis was that international adoptees might have faced ethnic discrimination as they entered the school years and might have experienced a longer period of exposure to pre-adoption adversity in their country of origin, which would lead to a higher risk for psychiatric distress," said Keyes, a research psychologist at the Minnesota Center for Twin and Family Research.
The assessments did find higher levels of separation anxiety among international adoptees.
Teachers also rated this group as significantly more anxious in general than their nonadopted peers.
Debbie Riley, executive director of the Center for Adoption Support and Education in suburban Washington, said that adopted young people faced added pressure at a vulnerable time of life.
"If ever there's a time when an adoptee is likely to enter therapy, it's during adolescence," Riley said.
Adopted children tend to be overrepresented among patients of mental health professionals, experts said.
Dr. Peter Nierman, a child psychiatrist who formerly reviewed applications for financial assistance from the state of Illinois for children with serious mental health problems, said requests from parents of adopted kids ran 10 to 20 times higher than for biological children.
Adoptive parents may be quicker to seek out such help because as a group they are better educated, have higher incomes and are more accepting of counseling.
"These are the only people who have to be approved for parenthood, so they are already involved with child welfare," said David M. Brodzinsky, a child psychologist and research director of the Evan B. Donaldson Adoption Institute in New York City.
But Keyes said her study suggested the differences between adopted and nonadopted adolescents could not be explained solely by parents' willingness to seek help.
Keyes stressed that her study should not alarm adoptive parents.
Being born male -- adopted or not -- also is a risk factor for disruptive behavior disorders, she said, "but no one is overly concerned when they give birth to a son."