Verheyden, Suzanne Louise; (2001) Psychopharmacological effects of ± 3,4 methylenedioxymethamphetamine (MDMA, ‘ecstasy’): mood and cognitive function in current and ex-users. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

This thesis aimed to investigate the effects of MDMA on aspects of memory, cognition and mood in people who currently use this drug and also in those who have stopped using. A review of the literature on the psychopharmacological effects of MDMA in animals and humans is presented before four empirical studies are reported. Study 1 was an exploratory examination of an opportunistic data set. Results of an interview survey with 466 regular users indicated that altered mood and impaired concentration were the sub-acute effects reported by over 80% of users. Results also showed that participants who used cocaine in conjunction with MDMA reported more negative effects than those who did not use this drug combination. Study 2 was a laboratory study with 96 volunteers. It used a tryptophan challenge technique to investigate 5-HT function in current and ex-users in comparison with a non-user control group. Ex-users showed a significantly greater increase than the other groups in total plasma tryptophan following a tryptophan augmented drink. Performance on a prose recall task was strongly and negatively correlated with change in free and total plasma tryptophan in ex-users. This group also showed positive correlations between baseline total plasma tryptophan and both frequency and length of MDMA use. Ex-users performed worse than other groups on several cognitive tasks; current users performed worse than controls on tasks tapping learning and higher cognitive function. Study 3 followed-up the findings of Study 2 by investigating the long-term effects of MDMA on mood in 66 ex-users. Results showed that ex-users who gave mental health reasons for abstaining from MDMA had higher trait depression scores than ex-users who gave other, circumstantial reasons for stopping. Study 4 was club-based and investigated whether there are gender differences in the acute and sub-acute effects of MDMA. 40 current users were tested on-drug and again 4 days later and compared with 40 MDMA-naive controls. Female MDMA users showed larger increases in depression scores from day 0 to day 4 than male users. This increase in depression in women was correlated with the amount of MDMA reportedly taken on day 0. Additionally, all MDMA users showed higher mid-week aggression scores than controls; in males this was correlated with the amount of MDMA taken on day 0. Taken together, these results suggest that MDMA users experience sub-acute alterations in mood. Further, some users may experience enduring cognitive and mood deficits that persist after they have stopped using MDMA. There are clear associations in ex-users between 5-HT function and both patterns of MDMA use and cognitive impairment. Further research is required to determine whether such alterations to 5-HT function are caused by or predate use of MDMA.

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