Auditory event-related potentials (P3) and cognitive performance in recreational ecstasy polydrug users: evidence from a 12-month longitudinal study

RATIONALE: There is important preclinical evidence of the long-lasting neurotoxic and selective effects of ecstasy (MDMA) on serotonin systems in nonhuman primates. In humans, long-term recreational use of ecstasy has been mainly associated with memory impairment. OBJECTIVE: The first aim of our study was to evaluate the cognitive and electrophysiological long-term alterations associated with lifetime ecstasy use within a sample of ecstasy polydrug users along a 1-year follow-up. Our second aim was to explore the relationship between specific cognitive functions and P300 (P3) event-related potentials (ERPs) in ecstasy users. MATERIALS AND METHODS: We conducted auditory P3 latency and amplitude and administered a battery of cognitive tests to three groups of subjects: 14 current ecstasy polydrug users, 13 current cannabis users, and 22 controls free of illicit drugs in two evaluations during 1 year. RESULTS: We found significant differences between ecstasy users and controls on cognitive measures of word fluency, processing speed, and memory recognition after 1-year follow-up. We found no significant differences between ecstasy and cannabis users or cannabis users and controls on cognitive tests. Lifetime ecstasy use was associated with poorer memory recognition. No group differences were shown on P3 latency or amplitude. Significant correlations emerged between P3 latency and cannabis lifetime use (higher cannabis use was related to faster latency, showing a paradoxical effect) but not with ecstasy exposure. CONCLUSIONS: Our findings provide evidence of mild long-term cognitive deficits among ecstasy polydrug users. Both ecstasy use and the dynamic interaction between ecstasy and cannabis effects may account for these deficits. No significant P3 alterations were found in ecstasy users.