Effects of MDMA on Social and Emotional Processing

The main aim of the study is to investigate the effects of ±3,4-methylenedioxymethamphetamine (MDMA; ecstasy) on social and emotional processing in healthy humans. Ecstasy is a widely used recreational drug, with over 2 million Americans reporting use of the drug in 2006. With this number of users, and evidence that high doses of MDMA are neurotoxic in laboratory animals, the public health implications of ecstasy use may be substantial. Certain subjective effects of this drug distinguish it from other stimulants, and may contribute to its widespread use: That is, users report that ecstasy produces profound feelings of empathy and closeness to others. These so-called 'empathogenic' effects, which may reflect the distinctive neurochemical profile of action of the drug, have yet to be characterized in controlled laboratory studies. The investigators propose to characterize the effects of MDMA on measures of social and emotional processing that may contribute to this 'empathogenic' profile, including measures of emotion recognition, emotional responsiveness and sociability. The investigators will assess effects of MDMA (0, 0.75 and 1.5 mg/kg up to 125 mg) one active control drug (oxytocin: 20 IU) in 100 volunteers who report some prior ecstasy use. Oxytocin will be used because it appears to produce pro-social behavioral effects resembling those attributed to MDMA.