NEW YORK (Reuters Health) - Research suggests that a "substantial minority" of American adults are reluctant to let their children interact with children who suffer from depression or attention deficit hyperactivity disorder.

About one out of five parents would not want these children as neighbors, in their child's classroom, or as their child's friend, report Jack K. Martin and colleagues from Indiana University in the Journal of Health and Social Behavior.

Older children and boys with mental conditions are most likely to be rejected.

This troubling pattern, the investigators report, appears to result from perceptions that a mentally ill child may be "dangerous."

"If, as it seems, the 'mental illness' of either children or adults signals danger to the public, this barrier must be addressed by future political, legal, and research agendas," according to Martin and colleagues.

The research stems from interviews with more than 1,100 adults as part of the General Social Survey administered by the National Opinion Research Center. The interviewees were given descriptions of children of various ages with asthma, attention deficit hyperactivity disorder, depression or "normal" ups and downs of childhood.

Levels of rejection for children with depression and ADHD were two to three times higher than those reported for children with asthma or "normal" childhood troubles.

The results showed that almost 30 percent of parents said they would not like their child to become friends with a child who was depressed and more than 18 percent wouldn't want to live next door to a family with a depressed child.

Roughly 23 percent of parents said they preferred that their child not make friends with a child with behaviors consistent with ADHD and 22 percent wouldn't want to live next door to a family with a child with ADHD.

"In line with the 1999 Surgeon General's report on mental illness, our analyses point to continuing barriers to public acceptance," note the report's authors. "While not as significant an obstacle as the rejection of adults, social distance does reflect stigma surrounding children's mental health problems."

They hope a greater understanding of the roots of this stigma will lead to effective efforts to confront the persistent lack of social acceptance of the mentally ill.