Recreational use of 3,4-methylenedioxymethamphetamine (MDMA) or 'ecstasy':evidence for cognitive impairment

Background. It has recently been shown that 3,4-methylenedioxymethamphetami ne (MDMA) or 'ecstasy' causes long-lasting alterations to brain structure a nd function in animals, and there is mounting evidence that recreational us ers of the drug show impairments in some aspects of cognitive functioning i ncluding memory for verbal information. The present study investigates poss ible effects on other cognitive functions and explores the temporal course of development and resolution of these impairments by comparing novice, reg ular and abstaining users with a matched group of non-users. Methods. Eighty participants categorized as non-users, novice users, regula r users or currently abstinent users of MDMA were assessed on tests of verb al IQ, reversed digit span, immediate and delayed recall of a prose passage and of a complex geometric figure and verbal fluency. Results. The four groups were well-matched for verbal IQ and on demographic variables. They differed in frequency of cannabis use over the last month, but this did not correlate with any cognitive test scores. All three group s of MDMA users showed significantly poorer verbal fluency and immediate an d delayed prose recall than non-users. Days since last use and total lifeti me consumption of MDMA made separate contributions to the variance in recal l scores, accounting jointly for almost half of the variance in delayed rec all. By contrast, the groups did not differ on either visual recall or reve rsed digit span. Conclusions. The observed deficits provide further evidence of impairments of verbal but not visual memory in MDMA users, and indicate that the defici ts are not attributable either to differences in general reasoning ability or to impairment of working memory. The data further suggest that the obser ved impairments may be attributable to a combination of reversible acute ef fects of MDMA resolving over a period of 2-3 weeks and more long-term chang es associated with extent of lifetime consumption.