Individual Differences in Acute Responses to MDMA in Humans: Effects of Sex and Past Ecstasy Use

Little is known about factors affecting individual differences in acute response to ±3, 4-methlyenedioxymethamphetamine (MDMA; ‘ecstasy’). To our knowledge, only one prior report has documented such differences in humans after controlled MDMA administration [1]. In that report, females had greater hallucinogenic and negative psychological responses to MDMA, whereas males showed greater cardiovascular responses. Here, we assessed sex differences in acute subjective and cardiovascular responses to MDMA (0.75mg/kg; 1.5mg/kg). In addition, because animal studies indicate that prior MDMA exposure produces lasting reductions in behavioral responses to the drug [2], we also examined effects of cumulative lifetime ecstasy use on acute MDMA effects.