The role of long- and short-term typical dose, concurrent alcohol consumption and executive processes in ecstasy related prospective memory deficits.

Abstract

Building on previous research demonstrating prospective memory (PM) deficits in ecstasy users the purpose of this thesis was to explore the specific nature of these deficits focussing on establishing dose related effects and exploring possible mediators. Using laboratory-based measures of PM and a detailed background drug use questionnaire, the extent to which the typical dose of ecstasy per session can predict PM performance was examined. In Chapter 7, increased dose of ecstasy per session (typical dose of ecstasy per session in the 12 months prior to the test-session) was associated with poor short-term time-based PM performance. Chapter 8 examined the effects of concurrent alcohol and ecstasy use on PM performance. The use of alcohol and ecstasy together was not associated with additional PM performance deficits. Chapter 10 investigated the role of executive functioning processes in accounting PM deficits in ecstasy users. Verbal word fluency, updating, shifting and inhibition executive functions did not predict PM performance in ecstasy users. Chapter 11 used correlational analyses to investigate the effects of long- and short-term indicators of ecstasy, cannabis and cocaine use on PM performance. Clear relationships were established between long-term indicators of ecstasy and cocaine use and PM performance. Total lifetime ecstasy and cocaine consumption and the long-term average dose of ecstasy and cocaine per session were related to PM performance. For both drugs, increased lifetime consumption and larger doses consumed in a typical session were associated with adverse outcomes on PM tasks.
PM impairments in ecstasy users were found in all studies in this thesis. These findings have important implications for those individuals who use ecstasy. Firstly, the use of ecstasy is detrimental to PM performance and therefore can potentially be debilitating to normal everyday functioning. More specifically, those individuals who consume higher doses of ecstasy per session may be more likely to display PM impairments compared to those individuals who consume lower doses. This information should be used to educate ecstasy users as to the possible consequences of its use. Future research should further explore the importance of typical dose of ecstasy per session in relation to cognitive performance in general. In addition to the administration of laboratory-based measures of PM, the use of neuroimaging techniques could be employed. This would allow researchers to potentially identify specific brain regions that may be implicated in PM deficits in those ecstasy users who consume large doses of ecstasy in a representative session.