Biological Psychiatry
June 3, 2019
Anya K. Bershad, Scott T. Schepers, Michael P. Bremmer et al.
176 citations
Single very low doses of LSD (6.5, 13, and 26 micrograms) produce dose-related subjective effects in healthy young adults. The highest dose (26 μg) increased ratings of vigor and slightly decreased positivity ratings of images with positive emotional content. Other mood measures, cognition, and physiological measures were unaffected. A threshold dose of 13 μg might be used safely in an investigation of repeated administrations. It remains to be determined whether the drug improves mood or cognition in individuals with symptoms of depression.
Psychoneuroendocrinology
April 19, 2014
M. Kirkpatrick, Sunday M. Francis, Royce J. Lee et al.
106 citations
MDMA (ecstasy) increases feelings of sociability and closeness. This study tested whether those effects come from a rise in the hormone oxytocin. In 14 healthy MDMA users given MDMA, oxytocin nasal spray, or placebo, only the higher MDMA dose (1.5 mg/kg) raised blood oxytocin levels to a peak of 83.7 pg/ml around 90–120 minutes, versus 18.6 pg/ml after placebo. The higher oxytocin spray (40 IU) raised levels to 48.0 pg/ml. MDMA increased heart rate, blood pressure, and feelings of euphoria and sociability, but oxytocin spray did not. The subjective effects of MDMA were not linked to oxytocin levels, suggesting oxytocin may not be the main cause of MDMA's prosocial effects.
Journal of Psychopharmacology
August 26, 2016
Anya K. Bershad, Melissa A. Miller, Matthew J. Baggott et al.
104 citations
MDMA, a recreational drug, enhances sociability and feelings of closeness more than other stimulants like dextroamphetamine, methamphetamine, and methylphenidate. This review compares human laboratory studies on the social effects of MDMA versus other stimulants, from simple ratings of sociability to complex social behaviors, and examines the neurochemical mechanisms involved. The findings suggest that MDMA's distinct prosocial effects may underlie its recreational use and potential as a psychotherapy aid, distinguishing it from typical stimulants.
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.
Psychopharmacology
March 15, 2014
M. Kirkpatrick, M. Baggott, J. Mendelson et al.
78 citations
Across three independent laboratories in Basel, San Francisco, and Chicago, 220 healthy volunteers received either placebo or MDMA (1.5 mg/kg or a 125-mg fixed dose) under double-blind conditions. Despite differences in study methods and participants' prior drug use, MDMA produced very similar cardiovascular and subjective effects at all sites. Prior MDMA use was inversely related to feeling "Any Drug Effect" only at sites testing more experienced users. The pharmacological effects of MDMA are robust and highly reproducible across settings, with modest evidence for tolerance in regular users.
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.
PLoS ONE
October 25, 2021
Annie Regan, Seth Margolis, Harriet de Wit et al.
18 citations
MDMA produces a moderate-to-large increase in self-reported feelings of sociability—such as feeling loving, talkative, and friendly—according to a meta-analysis of 27 placebo-controlled studies involving 592 participants. The overall effect size was d = 0.86, indicating a substantial boost in sociability-related outcomes. This finding suggests MDMA could have powerful implications for social interactions and clinical settings, such as in psychotherapy. The analysis highlights the need for larger experimental studies and further investigation into the mechanisms linking MDMA to enhanced social connection.
bioRxiv (Cold Spring Harbor Laboratory)
May 24, 2022
Manoj K. Doss, Jason Samaha, Frederick S. Barrett et al.
6 citations
preprint
Different classes of psychoactive drugs—sedatives, dissociatives, psychedelics, stimulants, and cannabinoids—each produce unique patterns of effects on the conscious processes underlying episodic memory, depending on whether they act during encoding, consolidation, or retrieval. Reanalyzing confidence data from 10 published datasets (28 drug conditions) with signal detection models, the authors found that all drugs except stimulants impaired recollection when given at encoding; sedatives, dissociatives, and cannabinoids also impaired familiarity at encoding. Psychedelics at encoding enhanced familiarity and did not affect metamemory, while dissociatives and cannabinoids tended to enhance metamemory. Stimulants enhanced metamemory at encoding and retrieval but impaired it at consolidation. These distinct profiles may help explain drug-specific subjective phenomena such as sedative-induced blackouts or psychedelic déjà vu.
Journal of Psychopharmacology
September 16, 2025
Ramona L. Martinez, Nina Radošić, Hanna Molla et al.
1 citation
MDMA increases feelings of trust in the social world beyond specific interaction partners in a lab setting. The findings align with user reports of generalized social well-being effects and suggest that MDMA may have clinical value from a social psychological perspective.