Washington ? Is it ethical in the name of science to give a healthy child as young as 9 a controlled substance? That’s the dilemma facing the Food and Drug Administration’s Pediatric Ethics subcommittee at its first-ever meeting Sept. 10.

The research, proposed by the National Institute of Mental Health, includes healthy children among 9- to 18-year-olds who would receive a single dose of dextroamphetamine.

The hoped-for payoff for research: A better understanding of how healthy brains work differently from those of children diagnosed with attention deficit hyperactivity disorder.

The payoff for families: $570.

Characterized by inattentiveness, overactivity and impulsiveness, ADHD affects up to 5 percent of schoolchildren. The disorder continues in roughly 60 percent of those youths as they age, although experts say the disorder is underdiagnosed in adults.

Dextroamphetamine, the active ingredient in such drugs as Dexedrine and Adderall, is prescribed commonly to increase attention span and calm restlessness. Doses vary with children’s needs, with daily doses as little as 5 mg. or as much as 30 mg.

Judith L. Rapoport, chief of child psychology at NIMH, within the National Institutes of Health, conducted a similar trial 20 years ago. The same stimulant was given to children at a higher dose. Researchers looked only at how the stimulant changed children’s behavior as they performed tasks. The stimulant improved attention span in the children, regardless of whether they had ADHD.

The new trial would add magnetic resonance images to map potential differences in brain activation patterns.

While Rapoport’s trial is little different from the earlier one, review boards that balance risk vs. scientific gain have changed dramatically in 20 years.

Indeed, an NIH review panel met twice and was unable to reach a consensus whether risk to healthy volunteers would be too high in the new study. They kicked the sensitive matter to the FDA’s new pediatrics ethics subcommittee.