How Does It Work?

By Christine Gorman

For a drug that's been used for more than a half-century, we know surprisingly little about how Ritalin acts on the brain or why it helps children with attention-deficit/hyperactivity disorder focus. For that matter, even ADHD is still something of a mystery to doctors, who speak of it sometimes as if it were a single condition and sometimes as if it were a broad range of problems. Researchers suspect that the disorder stems from an inadequate supply of dopamine and norepinephrine in the brain--a hypothesis that is supported in part by the fact that Ritalin boosts dopamine levels. But proof of any of this has been tough to come by.

So it should come as no surprise that the latest research raises more questions than it answers. The National Institutes of Health tried to cut through some of the confusion last week by playing host to a consensus conference to determine what--if anything--the experts can agree on. Among the findings:

--Ritalin clearly works in the short term to reduce the symptoms of ADHD. But more and more kids have been taking the drug for years, and no studies have run long enough to see if it has a lasting effect on academic performance or social behavior.

--Overall, Ritalin seems to be a pretty safe drug. It does stifle appetites, at least in the beginning, and it may cause insomnia. It can interfere with a child's growth rate, although the latest research suggests that it only delays--rather than stunts--a youngster's development. While there has been an increase in the number of stimulant prescriptions for children under five, there is no evidence that these drugs are safe or effective used on young children.

--A positive response to Ritalin doesn't automatically mean a child suffers from ADHD. Stimulants can temporarily sharpen almost anyone's focus.

--Ritalin is not a panacea. It won't boost IQ or take away the learning disabilities that affect 15% of youngsters with ADHD.

--It's not always clear how to treat children whose main symptom isn't hyperactivity but "inattention" or daydreaming, a problem that affects more girls with ADHD than boys.

--Preliminary evidence suggests that the brains of children with ADHD are somehow different from those of their unaffected peers. But no one knows for sure whether that is due to normal variation or the result of a true biochemical defect.

--There has been intriguing work to suggest that at least some children with ADHD may respond to nutritional treatments, including the addition of certain fatty oils or the elimination of other foods from their diet. But in a phrase that was repeated so often last week that it could become a registered trademark, panelists concluded that more research is needed.

--By Christine Gorman. Reported by Ann Blackman/Washington

With reporting by Ann Blackman/Washington