The researchers assessed 514 internationally adopted adolescents and 178 domestically adopted adolescents (aged 11 to 21) and compared them with 540 non-adopted kids of the same age.
Children who had been adopted scored higher than non-adoptees on continuous measures of behavioral and emotional problems, the team found. Adoptees were about twice as likely to have had contact with a mental health professional and of having a disruptive behavior disorder, according to the study.
Domestic adoptees were more than twice as likely to have an "externalizing disorder" (one that manifests in outward behavior) than international adoptees, the researchers added.
As one example, seven out of every 100 non-adopted kids met the criteria for ADHD (attention deficit hyperactivity disorder), while 14 to 15 of adopted kids met the criteria, Keyes said. Still, the overall rate was not alarming.
To put it into perspective, Keyes pointed out that simply giving birth to a male is risky, since boys have a higher chance of being diagnosed with a disruptive behavior disorder than girls.
"It's important not to stigmatize adoption," Pertman said. "Adoption is not causing these problems."
A second study in the same issue of the journal looked at children who had lost a parent to death suddenly. Researchers at the University of Pittsburgh School of Medicine found that these bereaved youngsters had triple the risk of depression and post-traumatic stress disorder (PTSD) than kids with two parents still alive.
According to the article, 4 percent of children in Western countries have experienced the death of a parent.
More information
There's more on adoption at the Evan B. Donaldson Adoption Institute.
