Journal of Psychopharmacology
March 4, 2015
Matthew G. Kirkpatrick, Andrew W. Delton, Theresa E. Robertson et al.
86 citations
MDMA increases generosity, but the effect depends on the recipient's social closeness. In two studies, participants decided whether they or another person would receive money. Without MDMA, people were more generous toward close friends than acquaintances or strangers; generosity was linked to household income and the personality trait Agreeableness. After a high dose of MDMA (1.0 mg/kg), generosity increased only toward a friend. A lower dose (0.5 mg/kg) slightly increased generosity toward a stranger, especially among women. The findings suggest MDMA's prosocial effects are selective, similar to oxytocin, and depend on relationship proximity.
Journal of Psychopharmacology
April 29, 2015
Matthew J. Baggott, Matthew G. Kirkpatrick, Gillinder Bedi et al.
69 citations
MDMA increases the use of social, sexual, and emotional words during conversation. In a double-blind, within-subjects study, 35 healthy volunteers who had previously used MDMA received either 1.5 mg/kg oral MDMA or a placebo and then discussed a close personal relationship for five minutes. Both a standard dictionary method and a machine learning analysis showed that MDMA altered speech content: it boosted social and sexual words, and also increased words related to both positive and negative emotions. These changes in speech content may help explain how MDMA enhances sociability and emotional connection during social interactions.
Social Cognitive and Affective Neuroscience
March 27, 2014
Margaret C. Wardle, Matthew G. Kirkpatrick, Harriet de Wit
52 citations
MDMA (ecstasy) increases positive emotional responses specifically to pictures containing people, while reducing positive responses to non-social positive pictures. In two studies with 101 healthy occasional MDMA users, participants rated their reactions to positive, negative, and neutral images with and without social content after receiving different doses of MDMA. The drug did not simply amplify all positive feelings; instead, it selectively enhanced the appeal of social scenes. This suggests MDMA's prosocial effects—such as increased closeness and sociability—may arise from making social contact feel more valuable relative to non-social rewards, which could explain its recreational appeal and potential therapeutic use in psychotherapy.
Social Neuroscience
January 20, 2016
Anya K. Bershad, Jessica Weafer, Matthew G. Kirkpatrick et al.
35 citations
MDMA (ecstasy) increases sociability and empathy, likely through the release of oxytocin. A single-letter variation in the oxytocin receptor gene (OXTR rs53576) influences how people respond to the drug. In a double-blind, within-subjects study, 68 healthy volunteers with past MDMA experience received placebo, 0.75 mg/kg, or 1.5 mg/kg of MDMA. At the higher dose, individuals with the A/A genotype did not show the increase in sociability seen in G allele carriers. No genotypic differences appeared at the lower dose or in cardiovascular or other subjective effects. The results suggest MDMA-induced sociability depends on oxytocin signaling and that genetic variation in the oxytocin receptor modulates the drug's social effects.
Neuropsychopharmacology
January 24, 2020
Carla Agurto, Guillermo Cecchi, Raquel Norel et al.
33 citations
Computer-extracted speech features from acoustic, semantic, and psycholinguistic domains can detect mental states after controlled administration of MDMA and intranasal oxytocin. In a double-blind, placebo-controlled study with 31 healthy adults, speech tasks during peak drug effects yielded cross-validated accuracies up to 87% in the training/validation set and 92% in independent datasets for classifying drug conditions. Oxytocin-driven changes were mostly captured by acoustic features related to emotion and prosody, while MDMA-related mental states manifested across multiple speech domains. The experimental task—whether involving interaction with another individual—also affected speech responses. These results suggest speech analysis can provide objective markers of drug-induced mental states.