Sunday November 11 4:14 PM ET

Ritalin May Change Brain Long-Term, Study Shows

WASHINGTON (Reuters) - The stimulant Ritalin, a drug used to help children with attention deficit hyperactivity disorder, may cause long-term changes in the brain, researchers reported Sunday.

The changes look similar to those seen with other stimulants such as amphetamine and cocaine, at least in rats, the team at the University of Buffalo found.

``Clinicians consider Ritalin to be short-acting,'' Joan Baizer, a professor of physiology and biophysics who led the study said in a statement.

``When the active dose has worked its way through the system, they consider it 'all gone.' Our research with gene expression in an animal model suggests that it has the potential for causing long-lasting changes in brain cell structure and function.''

But Baizer said that Ritalin, known generically as methylphenidate, probably is not addictive in the way drugs of abuse are if it is used properly.

``Children have been given Ritalin daily for many years, and it is extremely effective and beneficial, but it's not quite as simple as a short-acting drug,'' she said. ``We need to look at it more closely.''

High doses of amphetamine and cocaine have been found to switch on genes known as ``immediate early genes'' in brain cells. One of the genes, called c-fos, has been linked with addiction when it is activated in certain parts of the brain.

The researchers gave rat pups sweetened milk carrying methylphenidate in comparable doses and at similar times to what a child would get.

C-fos genes were activated in their brains in a pattern similar to that seen in cocaine and amphetamine use, the researchers told a meeting of the Society for Neuroscience in San Diego.

``These data do suggest that there are effects of Ritalin on cell function that outlast the short term and we should sort that out,'' Baizer said.

She said perhaps a gene chip -- a microarray -- could be used to see just which genes are turned on and off by methylphenidate.

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