Human Research on MDMA (3,4-Methylene- dioxymethamphetamine) Neurotoxicity: Cognitive and Behavioural Indices of Change

Repeated use of MDMA (Ecstasy) can damage serotonin-producing neurons in laboratory animals, and a similar pattern may occur in humans. A review of drug-free recreational Ecstasy users found consistent impairments in three cognitive areas: memory for new information, higher-level executive processing, and increased impulsivity. Basic cognitive functions like reaction time, vigilance, and Stroop performance remained intact. Some users reported memory and concentration problems they attributed to MDMA. Methodological issues, such as non-random assignment and other drug use, complicate the findings. The pattern of deficits matches animal data showing serotonergic damage in the frontal cortex and hippocampus, and aligns with a hypothetical construct of reduced cortical inhibition.

Study at a glance

Abstract

Laboratory animals can develop serotonergic neurotoxicity after repeated doses of 3,4-methylenedioxymethamphetamine (MDMA) or ‘Ecstasy’. If similar neural damage occurs in humans, this may be evident in cognitive or behavioural impairments. In a review of the behavioural skills shown by drug-free recreational Ecstasy users, three aspects of cognitive performance are often affected: reduced memory for new information (Rivermead Behavioral Memory, supraspan word recall), impaired higher executive processing (Wisconsin Card Sort, Tower of London), and heightened impulsivity (Impulsiveness, Venturesomeness and Empathy Questionnaire, Matching Familiar Figures test). Performance on other more basic cognitive functions is generally unimpaired (simple reaction time, choice reaction time, number vigilance, Stroop, trail making). Some Ecstasy users also complain of poor memories and/or concentration difficulties, which they attribute to MDMA use. There are many methodological problems and uncertainties with research in this field: non-random allocation of subjects to drug conditions, the deleterious effects of other psychoactive drugs, and the possibility that these adverse profiles reflect pre-existing personality characteristics in Ecstasy users. However, this particular pattern of cognitive decrements in humans, is consistent with the animal data on those brain areas showing serotonergic damage following MDMA: the frontal cortex (impulsivity and higher cognitive impairments), and hippocampus (memory deficits). Finally, this profile of cognitive deficits is also consistent with a hypothetical integrative construct: namely reduced cortical inhibition.