Cognitive performance in recreational ecstasy polydrug users: a two-year follow-up study

There is important preclinical evidence of long lasting neurotoxic and selective effects of ecstasy MDMA on serotonin systems in non-human primates. In humans long-term recreational use of ecstasy has been mainly associated with learning and memory impairments. The aim of the present study was to investigate the neuropsychological profile associated with ecstasy use within recreational polydrug users, and describe the cognitive changes related to maintained or variable ecstasy use along a two years period. We administered cognitive measures of attention, executive functions, memory and learning to three groups of participants: 37 current polydrug users with regular consumption of ecstasy and cannabis, 23 current cannabis users and 34 non-users free of illicit drugs. Four cognitive assessments were conducted during two years. At baseline, ecstasy polydrug users showed significantly poorer performance than cannabis users and non-drug using controls in a measure of semantic word fluency. When ecstasy users were classified according to lifetime use of ecstasy, the more severe users (more than 100 tablets) showed additional deficits on episodic memory. After two years ecstasy users showed persistent deficits on verbal fluency, working memory and processing speed. These findings should be interpreted with caution, since the possibility of premorbid group differences cannot be entirely excluded. Our findings support that ecstasy use, or ecstasy/cannabis synergic effects, are responsible for the sub-clinical deficits observed in ecstasy polydrug users, and provides additional evidence for long-term cognitive impairment owing to ecstasy consumption in the context of polydrug use.