No Evidence that MDMA-Induced Enhancement of Emotional Empathy Is Related to Peripheral Oxytocin Levels or 5-HT1a Receptor Activation

• Published in: PloS one Vol. 9; no. 6; p. e100719
• Main Authors: Kuypers, Kim P. C., de la Torre, Rafael, Farre, Magi, Yubero-Lahoz, Samanta, Dziobek, Isabel, Van den Bos, Wouter, Ramaekers, Johannes G.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.06.2014; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Behavior; Biology and Life Sciences; Cognition & reasoning; Cognitive ability; Drogoaddicció; Drug abuse; Ecstasy; Emotions; Emotions - drug effects; Empathy - drug effects; Female; Humans; Interpersonal Relations; Investigació; Male; MDMA; MDMA (Droga); Medicine and Health Sciences; Metabolisme; Models animals; N-Methyl-3,4-methylenedioxyamphetamine - blood; N-Methyl-3,4-methylenedioxyamphetamine - pharmacology; N-Methyl-3,4-methylenedioxyamphetamine - therapeutic use; Neuropsychology; Neurosciences; Oxytocin; Oxytocin - blood; Oxytocin - pharmacology; Oxytocin - therapeutic use; Pharmacology; Pindolol; Pindolol - blood; Pindolol - pharmacology; Pindolol - therapeutic use; Placebo Effect; Plasma levels; Psychology; Psychopharmacology; Receptor mechanisms; Receptor, Serotonin, 5-HT1A - metabolism; Receptors; Reciprocity; Serotonin; Serotonin S1 receptors; Social behavior; Studies; Substance-Related Disorders - drug therapy; Surveys and Questionnaires; Vasopressin; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0100719

The present study aimed at investigating the effect of MDMA on measures of empathy and social interaction, and the roles of oxytocin and the 5-HT1A receptor in these effects. The design was placebo-controlled within-subject with 4 treatment conditions: MDMA (75 mg), with or without pindolol (20 mg), oxytocin nasal spray (40 IU+16 IU) or placebo. Participants were 20 healthy poly-drug MDMA users, aged between 18-26 years. Cognitive and emotional empathy were assessed by means of the Reading the Mind in the Eyes Test and the Multifaceted Empathy Test. Social interaction, defined as trust and reciprocity, was assessed by means of a Trust Game and a Social Ball Tossing Game. Results showed that MDMA selectively affected emotional empathy and left cognitive empathy, trust and reciprocity unaffected. When combined with pindolol, these effects remained unchanged. Oxytocin did not affect measures of empathy and social interaction. Changes in emotional empathy were not related to oxytocin plasma levels. It was concluded that MDMA (75 mg) selectively enhances emotional empathy in humans. While the underlying neurobiological mechanism is still unknown, it is suggested that peripheral oxytocin does not seem to be the main actor in this; potential candidates are the serotonin 2A and the vasopressin 1A receptors. Trial registration: MDMA & PSB NTR 2636.