A new report from US scientists which says taking ecstasy several times a night may speed up the onset of Parkinson's disease has been disputed by a New York professor.
A study on monkeys in Stanford University found it damaged key neurons in the brain, but some experts are disputing the relevance of the findings.
A Stanford University researcher injected squirrel monkeys and baboons with three shots of Ecstasy, also known as MDMA, three hours apart, mimicking dosages "often used at all-night dance parties."
He said the drug caused enduring damage to dopamine-producing neurons in the brains of the animals, but said the study wasn't clear on whether the damage would be repaired over a lifetime.
However, the damage "was still evident two to six weeks later," said Dr George A Ricaurte, the lead author of a study appearing this week in the journal Science.
Ricaurte said the damage was not enough to cause Parkinsons symptoms, but does raise a "clinical concern" as Parkinson's disease, is known to be triggered by severe and permanent loss of dopamine-producing nerve cells.
Dr Julia A Holland, an NYU associate professor, said earlier studies on humans have failed to show that ecstasy causes permanent damage to dopamine neurons.
And she said Ricaurte's study had also failed to prove its relevance to humans.
"The dose that he gave killed 20 per cent of the animals immediately. Clearly these animals reacted to the drug differently than humans because not one out of five Ecstasy users drops dead," she said.
"It is because of Ricaurte's research that the government has been able to demonise Ecstasy for so long. I believe therapeutic MDMA use under medical supervision may be beneficial. When the government focuses on recreational use and prevents therapeutic research from going forward concerns me."