Neuropsychological evidence of a relatively selective profile of temporal dysfunction in drug-free MDMA ("ecstasy") polydrug users

Abstract

Rationale: Experimental evidence has shown that 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") can act as a serotonergic neurotoxin in laboratory animals. The serotonin system predominantly innervates frontal and limbic regions of the brain and has been associated with consolidatory learning and mnemonic processes in humans.

Objectives: The aim of the present study was to investigate the cognitive neuropsychological profile of drug-free ecstasy users by employing a selection of tasks previously associated with lesion or neurodegenerative damage to the temporal lobe or fronto-striatal regions.

Methods: The study comprised 40 participants: 20 ecstasy polydrug users and 20 polydrug users who had never taken ecstasy.

Results: Ecstasy users were significantly impaired on a recognition task for complex visual patterns and spatial working memory, as a function of task difficulty rather than systematic search strategy. They also showed a trend towards impairment on several learning paradigms. Ecstasy users remained relatively unimpaired on most measures associated with prefrontal functioning, with the exception of verbal fluency "letter" generation.

Conclusions: Initial cognitive deficits in ecstasy polydrug users may be more apparent in tasks known to be sensitive to temporal functioning.