Differential effects of MDMA and methylphenidate on social cognition.
Social cognition is important in everyday-life social interactions. The social cognitive effects of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and methylphenidate (both used for neuroenhancement and as party drugs) are largely unknown. We investigated the acute effects of MDMA (75 mg), methylphenidate (40 mg) and placebo using the Facial Emotion Recognition Task, Multifaceted Empathy Test, Movie for the Assessment of Social Cognition, Social Value Orientation Test and the Moral Judgment Task in a cross-over study in 30 healthy subjects. Additionally, subjective, autonomic, pharmacokinetic, endocrine and adverse drug effects were measured. MDMA enhanced emotional empathy for positive emotionally charged situations in the MET and tended to reduce the recognition of sad faces in the Facial Emotion Recognition Task. MDMA had no effects on cognitive empathy in the Multifaceted Empathy Test or social cognitive inferences in the Movie for the Assessment of Social Cognition. MDMA produced subjective empathogenic effects, such as drug liking, closeness to others, openness and trust. In contrast, methylphenidate lacked such subjective effects and did not alter emotional processing, empathy or mental perspective-taking. MDMA but not methylphenidate increased the plasma levels of oxytocin and prolactin. None of the drugs influenced moral judgment. Effects on emotion recognition and emotional empathy were evident at a low dose of MDMA and likely contribute to the popularity of the drug.