The harmful health effects of recreational ecstasy: a systematic review of observational evidence.

OBJECTIVES To investigate the harmful health effects of taking ecstasy (3,4-methylenedioxymethamphetamine, MDMA) for recreational purposes. DATA SOURCES MEDLINE, EMBASE, PsycINFO and Web of Knowledge were searched. Additional information on deaths was collected from the General Mortality Register (GMR) and the Special Mortality Register collated by the National Programme on Substance Abuse Deaths (np-SAD). REVIEW METHODS Studies were categorised according to design, with systematic research syntheses (Level I evidence) the most valid and least open to bias. Where Level I evidence was not available, controlled observational studies (Level II evidence) were systematically reviewed. If neither Level I nor Level II evidence was available, uncontrolled case series and case reports (Level III evidence) were systematically surveyed. Data were extracted by one reviewer and a sample checked by a second. The heterogeneity of Level II evidence was addressed by undertaking stratified analyses for current and former ecstasy users and comparing them either with control groups using other illegal drugs but not ecstasy (polydrug controls) or with controls naïve to illegal drugs (drug-naïve controls). Statistical heterogeneity was minimised by using a random-effects model throughout and investigated using study-level regression analysis (metaregression). RESULTS Five Level I syntheses were identified; for each it was difficult to ascertain the exact methods adopted and evidence included. Small but significant deficits for ecstasy users compared to controls were reported in areas relating to attention, memory, psychomotor speed, executive systems functioning, and self-reported depressive symptoms. Data from Level II studies were directly pooled for seven individual outcomes, suggesting that ecstasy users performed worse than controls on common measures of immediate and delayed verbal recall (RAVLT, RBMT, digit span). No difference was seen in IQ (NART). The 915 outcome measures identified in Level II studies were analysed in broad domains: immediate and delayed verbal and visual memory, working memory, two measures of attention, three measures of executive function, perceptual organisation, self-rated depression, memory and anxiety, and impulsivity measured objectively and subjectively. Ecstasy users performed significantly worse than polydrug controls in 13/16 domains and significantly worse than drug-naïve controls in 7/12 domains for which sufficient data were available. The largest, most consistent exposure effects were seen in meta-analyses of memory (especially verbal and working memory, with less marked effects seen in visual memory). Former ecstasy users frequently showed deficits that matched or exceeded those seen amongst current users. At aggregate level, the effects do not appear to be dose-related, but are variably confounded by other drug use, particularly alcohol. Of Level III evidence, in the 10 years to 2006, the np-SAD and the GMR recorded an average of around 50 drug-related deaths per year involving ecstasy; it was the sole drug implicated in around 10 cases per year. Retrospective case series, based on hospital emergency department records, reported a death rate of 0-2% from emergency admissions related to ecstasy. Two major syndromes are most commonly reported as the immediate cause of death in fatal cases: hyperthermia and hyponatraemia. CONCLUSIONS A broad range of relatively low-quality literature suggests that recreational use of ecstasy is associated with significant deficits in neurocognitive function (particularly immediate and delayed verbal memory) and increased psychopathological symptoms. The clinical significance of the exposure effect in individual cases will be variable but, on average, deficits are likely to be relatively small. Ecstasy is associated with a range of acute harms but appears to be a rare cause of death in isolation.