Ecstasy use: cognitive deficits related to dosage rather than self-reported problematic use of the drug.

Previous research has shown drug-free Ecstasy users to demonstrate selective cognitive impairment. However, there seems to be a degree of individual variation in the occurrence of such deficits. The present study aimed to assess whether these cognitive deficits are related to an awareness of problematic Ecstasy use, or to past drug dosage. Twenty regular Ecstasy users who reported experiencing Ecstasy-related problems were compared with 20 Ecstasy users who had not reported any previous problems. The two groups displayed similar past histories in relation to a range of illicit drugs, and were divided into low, medium and high users. The controls comprised 20 illicit recreational drug users who had never taken Ecstasy. Executive task measures comprised the Tower of London (TOL), the Wisconsin Card Sorting Task (WCST) and spatial working memory. Immediate and delayed word recall, matched verbal recognition and recall and simple reaction time were also included. Both Ecstasy groups performed significantly worse than controls on two executive measures: TOL planning time and spatial working memory score. There were no differences in cognitive impairment between the Ecstasy users who complained of problems and those who did not. In both groups, decrement on executive tasks was demonstrated as a function of previous drug dose. The study confirms that heavy Ecstasy polydrug use may culminate in selective executive deficits. It also demonstrates that two differently self-perceived Ecstasy groups showed similar cognitive impairment, despite only one group complaining of problems. Because all Ecstasy participants also consumed a range of other illicit drugs, the results are reflective of Ecstasy polydrug use in individuals who use Ecstasy as a drug of preference.