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Ritalin May have Long-Term Side Effects

Excerpted from an article in the Telegraph (UK) titled "Ritalin May have Long-Term Side Effects"

RITALIN, the "chemical cosh" prescribed to about 25,000 British children, triggers changes to the brain long after its calming effects have worn off, scientists report today.

Researchers believe that Ritalin is safe, but say that questions remain about its long-term side effects. The changes, which are not fully understood, are similar to those occurring with other forms of amphetamine and also cocaine.

Ritalin is a mild amphetamine prescribed to children with attention deficit hyperactivity disorder. It works on the central nervous system as a stimulant, and as well as calming hyperactive youngsters, can leave some feeling lethargic, depressed or withdrawn.

In America, where up to 40 per cent of pupils in some schools are on medication for ADHD, there are concerns that the drug is given inappropriately to naturally boisterous, but otherwise healthy, children.

Last year, the Government's watchdog, the National Institute for Clinical Excellence, recommended that Ritalin be made available on the NHS for children with serious hyperactivity.

Now scientists at the University at Buffalo, New York, have shown that the drug methylphenidate, the generic form of Ritalin, may have long-term effects on brain function.

Dr Joan Baizer, who is due to present the study at the Society for Neuroscience in San Diego, California, said: "Clinicians consider Ritalin to be short-acting. 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.

"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. We need to look at it more closely."

Although the changes are similar to those seen with cocaine, there is no evidence that the low doses given to children are likely to lead to addiction.

Br Baizer added: "Ritalin does appear to be safe when used properly, but it is still important to ask what it is doing in the brain."

High doses of amphetamine and cocaine switch on certain genes in particular brain cells which alter the way nerve cells work. One of these genes is called c-fos and is known to be involved in movement and motivation in part of the brain known as the striatum.

The team wanted to see if the drug caused c-fos activation in the same parts of the brain, and at the same levels, as the other drugs.

Using young rats as an animal model, they gave one group sweetened milk containing a relatively high dose of methylphenidate. The dose was designed to mimic the effects of Ritalin on children. The other group was given ordinary sweetened milk.

After 90 minutes, the brains of both groups were analyzed for the presence of c-fos. Results showed there were many more neurons with c-fos activity in the brains of rats given methylphenidate, particularly in the striatum, than in the brains of control rats.

Dr Baizer said: "These data do suggest that there are effects of Ritalin on cell function that outlast the short term and we should sort that out. There is no indication of tolerance, but we have no idea if there is adaptation to the effects."