Acute psychological and physiological effects of MDMA ("Ecstasy") after haloperidol pretreatment in healthy humans

3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") releases serotonin and dopamine. The role for dopamine in mediating the effects of MDMA has not ye t been examined in humans. We investigated the effect of pretreatment with the dopamine D-2 antagonist haloperidol (1.4 mg i.v.) on psychological and physiological responses to MDMA (1.5 mg/kg p.o.) in 14 healthy volunteers u sing a double-blind placebo-controlled within-subject design. Subjective pe ak effects were rated using standardised scales. The physiological effects measured were blood pressure, heart rate and body temperature. Side effects were assessed during the session, and after 1 and 3 days. Haloperidol atte nuated MDMA-induced positive and mania-like mood but had no reducing effect on other subjective changes or on cardiovascular effects. Results are cons istent with a partial dopaminergic mediation of the euphoriant effects of M DMA. In contrast, dopamine does not seem to contribute to the physiological effects of MDMA, indicating a role for serotonin and norepinephrine. (C) 2 000 Published by Elsevier Science B.V.