It wasn’t really Ecstasy that caused the brain damage attributed to it:

“Scientists at Johns Hopkins University reported in September 2002 that key neurons in the brains of squirrel monkeys and baboons were damaged when the animals were given doses of Ecstasy that mimicked those often taken by users of the drug during ‘all-night dance parties.’

They said the study raised questions about whether Ecstasy, also known as MDMA, might hasten the onset of Parkinson’s disease, a disorder triggered by the permanent loss of dopamine-producing nerve cells. It was those nerve cells that were reported to have been damaged by Ecstasy in the Johns Hopkins research.

In retracting the story, the journal Science said Friday that the researchers had discovered that labels on drugs supplied to them by an outside company were incorrect, and the animals had actually been given a different drug, methamphetamine.” Salon

The research on MDMA’s side effects continues to be inconclusive and mixed; this retractions does not necessarily mean that heavy users should be reassured. In particular, the drug’s connection with the rave scene means it is often taken in combination with other substances and under circumstances that pose cardiovascular risks.