There is no evidence that ecstasy causes brain damage, according to one of the largest studies into the effects of the drug. Too many previous studies made over-arching conclusions from insufficient data, say the scientists responsible for the research, and the drug's dangers have been greatly exaggerated. The study was carried out by a team led by Professor John Halpern of Harvard Medical School and published in the journal Addiction last week. The finding will shock campaigners who have claimed ecstasy poses a real risk of triggering brain damage. They have argued that it can induce memory loss, decrease cognitive performance and has long-lasting effects on behaviour.