Reasoning deficits in ecstasy (MDMA) polydrug users

Abstract

2 ABSTRACT.Objectives. Previous research has shown that ecstasy users are impaired in thinking and reasoning. The present study sought to explore the possibility that syllogistic reasoning errors in ecstasy users were due to an inability to construct a model of the premises due to working memory limitations. Methods. Twenty-nine ecstasy users and 25 non-ecstasy user controls completed syllogistic reasoning problems varying in difficulty. Results. On the easier problems both groups performed at well above chance although nonusers achieved significantly more correct responses. Consistent with existing research, on the more difficult problems, errors by nonusers were characterised by incorrect conclusions suggesting that while nonusers have the working memory capacity to construct a single model of the premises, this is not an exhaustive representation and usually results in an erroneous conclusion. On the other hand for all problem types ecstasy users, rather than produce incorrect responses, were more likely to fail to generate a conclusion. Conclusions. The present results are consistent with the possibility that ecstasy users with their reduced working memory capacity may experience difficulty in constructing even a single model of the premises. While this might be attributable to the effects of MDMA neurotoxicty, many of the ecstasy users in the present study were polydrug users. Thus the possibility that other drugs including cannabis and cocaine might contribute to the present results cannot be excluded.

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

“…With regard to information processing speed, the data were originally collected by Wareing (2005); the random letter generation data were originally collected by Wareing et al (2002) and Fisk et al (2004); the reading span. data by Wareing et al (2004); the computation span data by Wareing et al (2004, and Montgomery et al (2005b); the spatial working memory data by Wareing et al (2005); the associative learning data from Montgomery et al (2005a); and the syllogistic reasoning data from Montgomery et al (2005c) and Fisk et al (2005).…”

“…Previous research from our laboratory has revealed a range of cognitive deficits in ecstasy users (e.g., Fisk et al 2005;Montgomery et al 2005b;Wareing et al 2005). However, we have not previously discriminated between individuals who consume ecstasy on its own and those who routinely take the drug with cannabis.…”

Reasoning deficits among illicit drug users are associated with aspects of cannabis use

“…Furthermore, while Montgomery et al (2005) linked this outcome specifically with ecstasy use, Fisk et al (2005) found that various measures of ecstasy, cannabis and cocaine were associated with errors on the task. However, dose-related effects have yet to be systematically examined and the possibly confounding effects of legal drugs such as alcohol and tobacco have been overlooked.…”

“…This will also allow for the increasing prevalence of polysubstance use to be addressed more effectively. For example, while less than half of Fisk et al's (2005) ecstasy users were also using cocaine, the increased use of this drug among young adult recreational users has meant that it is not unusual to find that up to cannabis (e.g., Hadjiefthyvoulou et al 2011).…”

“…In a further departure from Fisk et al's (2005) approach, while in the present study we use the same four one model syllogisms as they and Montgomery et al (2005) used, here we have not included the more difficult two and three model problems. Fisk et al (2005) and Montgomery et al (2005) found that these elicited a success rate that was little better than chance among their participants.…”