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Monday, 12 November, 2001, 00:38 GMT
Ritalin brain change claims disputed
ritalin
Ritalin is a controversial drug
A study which suggests the controversial drug Ritalin could cause long-term brain changes has been attacked.

The drug is prescribed to children with attention deficit hyperactivity disorder (ADHD).

While many parents say it has been extraordinarily successful, others have compared the drug to a "chemical cosh".

Scientists found that rats given large doses of Ritalin suffered subtle neuronal changes.

They said these were comparable to the effects of other stimulant drugs such as amphetamines and cocaine.


Our research...suggests that it has the potential for causing long-lasting changes

Dr Joan Brazier, University of Buffalo
However a UK expert who strongly advocates Ritalin use said the study was deeply flawed.

Dr Peter Cosgrove, who prescribes Ritalin to children at his private practice in Bristol, insists there is no evidence of long-term detrimental effects of taking the drug.

The doses given to the rats were far in excess of those given to children, he said.

Different metabolism

The research was carried out at the University of Buffalo.

Scientists gave one group of rats sweetened milk containing the high dose of Ritalin.

They said the differing metabolism of the rat meant this was equivalent to the upper end of the scale of dosage given to children.

Then they tested for changes in "immediate early genes" within brain cells.


There is no evidence of any long-term detrimental effects of taking Ritalin - the only long-term effects I know of are improvements in education, social relationships and self-esteem

Dr Peter Cosgrove

It is known that amphetamines and cocaine change these genes, and that these changes apparently alter some aspects of nerve cell function.

One of the genes is called c-fos, and high levels in a particular part of the brain called the striatum have been linked to the mechanism of addiction.

In the rats given the Ritalin treatment, there were many more neurons with c-fos activity.

This is an effect which could in theory persist beyond the short-term therapeutic effects of the drug, say the researchers.

'Absurd'

Dr Joan Bazier, who led the study, said: "Clinicians consider Ritalin to be short-acting.

"Our research with gene expression in an animal model suggests that it has the potential for causing long-lasting changes."

She did say that there was no evidence that Ritalin, in normal low doses, could produce much potential for drug abuse.

But Dr Cosgrove labelled the study "absurd".

"The doses they are using are ridiculous," he said.

"They are giving 20mg per kg - I would normally prescribe between 0.3mg and 0.7mg per kg.

"There is no evidence of any long-term detrimental effects of taking Ritalin - the only long-term effects I know of are improvements in education, social relationships and self-esteem".

The research will be presented at the annual meeting of the Society of Neuroscience in the US.

See also:

02 Jul 01 | Scotland
Public inquiry call over drug
25 Mar 01 | Health
Hyperactivity under the spotlight
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