Double-blind, placebo-controlled crossover study (n=24) testing single-dose MDMA (75 mg), intranasal oxytocin (48 IU), MDMA+5-HT1A blocker (pindolol 20 mg), and placebo in healthy MDMA-experienced volunteers to investigate prosocial effects and mechanisms.
Randomized, double-blind, placebo-controlled within-subject crossover (Latin square) with four test days separated by a minimum 7-day washout; treatments: MDMA 75 mg oral capsule, MDMA+5-HT1A blocker (pindolol 20 mg), intranasal oxytocin (48 IU total), and placebo.
Outcomes include objective computer tasks of empathy and social interaction, control word-learning task, and blood measurements of MDMA, oxytocin and other treatment concentrations; also assessment of the moderating effect of serotonin transporter genotype.
Single-dose MDMA 75 mg (oral) as one condition of a 4-condition crossover (Latin square).
MDMA 75 mg capsule.
MDMA 75 mg with pindolol 20 mg (5-HT1A blocker) as combination condition; crossover.
Pindolol (Visken®) 20 mg capsule, peak ~60 min; given in combination condition.
Intranasal oxytocin condition (48 IU total) as one arm of the crossover.
Syntocinon® intranasal spray, total 48 IU (multiple inhalations as per protocol).
Matching placebo condition; part of 4-condition crossover.
Matching placebo capsules/sprays for each active condition.