MDMA (‘Ecstasy’) impairs categorization of brief fearful expressions

Abstract

MDMA (±3,4-methylenedioxymethamphetamine, ‘Ecstasy’) is said to have unique effects including increased empathy and sociability. However, the perceptual and emotional effects of MDMA have not been well-studied in a controlled laboratory setting. We conducted a within-subjects placebo-controlled study in which 16 participants (8 male, 8 female) received 1.5 mg/kg oral MDMA and placebo in separate sessions. We measured categorization of emotional facial expressions using a 4-alternative forced choice task where a face with a neutral expression briefly displayed either a happy, sad, angry, or fearful expression. Self-report sociability and plasma oxytocin were also measured. MDMA impaired categorization of brief fearful facial expressions, decreasing accuracy and a signal-detection measure of discrimination (d-prime). MDMA also increased plasma oxytocin concentrations and self-report sociability. MDMA may not increase empathic accuracy, but may instead decrease response to threat-related stimuli while increasing sociability.

Footnotes

 Support by NIDA DA016776.