Cita:In each experimental session the participants received a single divided dose of 80–180 mg MDMA or placebo. In the first experimental session, an initial dose of 80 mg was followed by a supplemental half-dose of 40 mg 1.5–2.5 h after the first dose. In the second and third experimental sessions, an initial dose of 120 mg was followed by a supplemental half-dose of 60 mg. If tolerability issues emerged with the initial dose or if participants declined, the protocol permitted the supplemental dose and/or dose escalation to be withheld. There were no instances in which the supplemental dose was withheld due to tolerability issues. Six participants chose either not to take the supplemental dose (n = 3, 1 MDMA) or not to escalate to the 120 mg dose (n = 3, 2 MDMA) in a total of six experimental sessions (2.3% of the total sessions across the study).