Ecstasy (MDMA) does not have long-term effects on aggressive interpretative bias: a study comparing current and ex-ecstasy users with polydrug and drug-naive controls.

+/-3, 4-methylenedioxymethamphetamine (MDMA or ecstasy) remains a widely used recreational drug, which, in animals, can produce long-lasting changes to the brain's serotonergic system. As serotonin has been implicated in human aggression, it is possible that ecstasy users are at risk of increased aggression even after prolonged abstention from the drug. The objective of this study was to indirectly assess aggression in current and abstinent ecstasy users using an information-processing paradigm that measures cognitive bias toward material with aggressive content. The task employed has previously shown increased aggressive bias 3-4 days after ecstasy use. An interpretative bias task was administered to 105 male participants: 26 ex-ecstasy users, 25 current ecstasy users, 29 polydrug using controls, and 25 drug-naive controls. Accuracy and response times to process and recognize ambiguous sentences were tested. There were no group differences in aggressive interpretative bias. All 4 groups processed neutral sentences faster than aggressive sentences and were subsequently faster and more confident in recognizing neutral compared with aggressive sentences. Further, self-ratings of aggression also showed no group differences, even though self-rated impulsivity was significantly higher in current ecstasy users than in drug-naive controls. The findings that all groups were biased toward neutral and away from aggressive interpretations of ambiguous sentences add to the existing body of knowledge in suggesting that increased aggression found in ecstasy users a few days after taking the drug is a transient phenomenon and not a long-term, persisting effect.