The recreational drug, 3,4-methylenedioxymethamphetamine (MDMA; 'Ecstasy'), is a synthetic amphetamine derivative and a serotonin neurotoxin. MDMA use is associated with cognitive dysfunction and impulsivity, but since polydrug abuse is common among users it is difficult to attribute these problems specifically to MDMA. Moreover, few studies have examined reward-related cognitive processes. Our...