NEW YORK (July 17, 2007) — Use of the attention deficit/hyperactivity disorder (ADHD) drug Ritalin by young children may cause long-term changes in the developing brain, suggests a new study in an animal model by a research team at Weill Cornell Medical College in New York City.

The study is among the first to probe the effects of Ritalin (methylphenidate) on the neurochemistry of the developing brain. Between 2 to18 percent of American children are thought to be affected by ADHD, and Ritalin, a stimulant similar to amphetamine and cocaine, remains one of the most prescribed drugs for the behavioral disorder.

“These brain tissue findings revealed Ritalin-associated changes in four main areas,” Dr. Milner says. “First, we noticed alterations in brain chemicals such as catecholamines and norepinephrine in the rats’ prefrontal cortex — a part of the mammalian brain responsible for higher executive thinking and decision-making. There were also significant changes in catecholamine function in the hippocampus, a center for memory and learning.”

Treatment-linked alterations were also noted in the striatum — a brain region known to be key to motor function — and in the hypothalamus, a center for appetite, arousal and addictive behaviors.

Dr. Milner stressed that, at this point in their research, it’s just too early to say whether the changes noted in the Ritalin-exposed brain would be of either benefit or harm to humans.