MDMA affects both error-rate dependent and independent aspects of decision-making in a two-choice prediction task

MDMA alters decision-making in a way that depends on the degree of success or failure. In a crossover trial with 42 healthy volunteers, a single 1.5 mg/kg oral dose of MDMA increased how much previous responses and stimuli influenced current choices, particularly when error rates were low (20% and 50%). The drug did not significantly change basic response characteristics like response latency or switching, and participants' self-assessed psychological states did not predict the decision-making patterns. These results suggest that acute MDMA affects success-related response selection during decision-making.

Study at a glance

Abstract

Decision-making, i.e. selecting an action from a number of alternatives when the outcome is uncertain, is a complex process that is important for everyday life. 3,4-Methylenedioxymethamphetamine (MDMA), also known as 'Ecstasy', is a widely used recreational drug that is known to increase serotonin (5-HT) and, to a lesser extent, dopamine (DA) in animals. This study examined whether MDMA alters decision-making in a way that depends on the degree of success and outcome.Forty-two normal, healthy volunteers were given placebo or 1.5mg/kg p.o. MDMA in a randomized crossover design. Subjects completed the two-choice prediction task 120min after administration of the drug. Decision-making characteristics were obtained at 20% error rate, 50% error rate or 80% error rate.MDMA affected decision-making via a process that is dependent on success or failure. Administration of MDMA increased the degree to which the previous response predicted the current response (mutual information) and the average response sequence predictability (average dynamical entropy) at low error rates. MDMA increased the degree to which the previous stimulus influenced the selection of the current response at 20%, 50% or 80% error rate. MDMA did not significantly alter basic response characteristics such as response latency or switching. Self-assessment of the psychological state induced by MDMA did not predict the MDMA induced decision-making patterns. These results support the hypothesis that acute administration of MDMA affects success-related response selection during decision-making.