Children's Use of Ritalin May Alter Brain

Ritalin, the drug commonly used to treat attention deficit/hyperactivity disorder (ADHD) in children, may have the potential to cause changes in their brains, according to a new study at Weill Cornell Medical College in New York.

The study, recently mentioned in the Journal of Neuroscience, was conducted by injecting baby male rats twice a day with Ritalin (methylphenidate) from a week after their birth until they were 35 days old. At the conclusion of the study, researchers found changes in four parts of the rats' brains.

"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," said Teresa Milner, senior author of the study and a professor of neuroscience at Weill Cornell, in a press release.

Changes were also detected in the hippocampus, which controls memory, as well as the striatum, which affects motor function. Finally, scientists saw alterations in the hypothalamus, the area of the brain involved in appetite, emotions and arousal.

Milner and Jason Gray, a graduate student who was a lead author on the study, noted that the doses of Ritalin used on the rats corresponded to a fairly high dose in human children. The rats were also treated with the drug at an earlier age than most human children begin treatment, though Gray noted that Ritalin studies are currently being conducted on 2- and 3-year-old children.

In addition to the changes in the rats' brains, researchers also noted that the rats lost weight, much like human patients do once starting on the drug. Also, three months after receiving their last Ritalin injections, the treated rats seemed to display fewer signs of anxiety than subjects that received no drugs.

Despite the results of the study, Milner said that Ritalin use isn't necessarily harmful to children. In fact, children who have ADHD may have an out-of-balance brain chemistry, and Ritalin may help restore the proper balance of chemicals. "On the other hand, in brains without ADHD, Ritalin might have a more negative effect," Milner said. "We just don't know yet."

It's also important to note that three months after they stopped receiving the drug, the rats' brains had mostly returned to normal - an encouraging find, Milner said, which may support the assertion that Ritalin should only be used in children over a short period of time. "We're concerned about longer-term use," she said.

Weill Cornell Medical College Press Release - "Pediatric Ritalin Use May Affect Developing Brain, New Study Suggests." Available at: http://news.med.cornell.edu/wcmc/wcmc_2007/07_17d_07.shtml

Wikipedia - "Hypothalamus." http://en.wikipedia.org/wiki/Hypothalamus