MDMA alters emotional processing and facilitates positive social interaction

Background: ±3,4-Methylenedioxymethamphetamine (MDMA, “ecstasy”) produces “prosocial” effects, such as feelings of empathy and closeness, thought to be important to its abuse and its value in psychotherapy. However, it is not fully understood how MDMA alters basic emotional processes to produce these effects or whether it produces corresponding changes in social behaviour. Here, we examined how MDMA affects perceptions of and responses to emotional expressions and tested its effects on behaviour during a social interaction. We also examined whether MDMA’s prosocial effects are related to a measure of abuse liability.Methods: Over three sessions, 36 healthy volunteers with previous ecstasy use received MDMA (0.75, 1.5 mg/kg) and a placebo under double-blind conditions. We measured (i) mood and cardiovascular effects, (ii) perception of and psychophysiological responses to emotional expressions, (iii) use of positive and negative words in a social interaction, and (iv) perceptions of an interaction partner. We then tested whether these effects predicted the desire to take the drug again.Results: MDMA slowed perception of angry expressions, increased psychophysiological responses to happy expressions, and increased positive word use and perceptions of partner empathy and regard in a social interaction. These effects were not strongly related to a desire to take the drug again.Conclusions: MDMA alters basic emotional processes by slowing the identification of negative emotions and increasing responses to positive emotions in others. Further, it positively affects behaviour and perceptions during actual social interaction. These effects may contribute to the efficacy of MDMA in psychotherapy but appear less closely related to its abuse potential.