Some assertions about the negative health affects of MDMA use are exaggerated, and researchers have been forced to retract their more extreme claims. Dr. George Ricuarte wrote the journal Science on Sept. 12, 2003:
"We write to retract our report 'Severe dopaminergic neurotoxicity in primates after a common recreational dose regimen of MDMA ('ecstasy')' (1), following our recent discovery that the drug used to treat all but one animal in that report came from a bottle that contained methamphetamine instead of the intended drug, MDMA. Notably, methamphetamine would be expected to produce the same pattern of combined dopaminergic/serotonergic neurotoxicity (2) as that seen in the animals reported in our paper (1)."

Source

Ricuarte, George A., Jie Yuan, George Hatzidimitriou, Branden J. Cord, Una D. McCann, "Retraction," Letter to Science Magazine, Sept. 12, 2003, Vol. 31, p. 1479.
http://www.maps.org/media/sci…