Role of Serotonin in Acute and Subacute MDMA Effects

Randomised, double‑blind, crossover (2×2) study in healthy adult volunteers comparing single doses of MDMA (1.5 mg/kg) with placebo; citalopram 20 mg or placebo is co‑administered to attenuate MDMA‑induced serotonin release.

Primary aim is to measure MDMA's emotional and acute/subacute effects and determine how serotonin depletion by citalopram alters those effects; outcomes include subjective emotional measures and physiological safety assessments.