‘Working memory deficits in current and previous users of MDMA (ecstasy)'

by Michelle Wareing, John E. Fisk and Philip N. Murphy

Published in the British Journal of Psychology (No.91, 2000), pp.181-188

This study was done by a group of social scientists from the Edge Hill College of Higher Education in Ormskirk, UK. They looked at the thinking performance of three groups of 10 people. One group were people who had never used any drugs, the second was a group who said they had stopped using drugs, and the third was a group of current users. The average age was 22 years, and most had at least 12 years of education. The people were recruited by word of mouth. The type of drugs used were MDMA, Amphetamines, Cocaine, LSD and Marijuana, although no current users listed using Cocaine. The most popular drugs after MDMA were Amphetamines, MJ and LSD. The groups of users and ex-users took just under 3.5 pills per night on average, at least once a week.

A series of test were done. These included a 'Central executive functioning' test, where people were asked to generate random letters, excluding vowels, in a series of tests with a time period that ranged from 4 seconds, to 2 secs to 1 secs. Another test was a 'State anxiety and arousal', which tested how one felt about a particular task and one's feelings about life as whole etc. The last was one to test Information processing speed. This required people to compare rows of three, six and nine letters. The letters were sometimes rearranged so although a row had the same letters, it would not read the same. The participants were tested individually.

Generally the results showed that current and previous users faired worse that the group of non-users. In particular, they had the most difficulty with the 1 second random letter test, where they performed only about 60% of that of the non-users, and marginally worse in the 2 and 4 second tests. The information processing rate was about the same, but the accuracy was slightly down, but not as significantly as above. The anxiety levels were higher in both groups of users. Only current users showed lower levels of arousal with previous users show higher levels of arousal than the non-users.

The primary problem that has been raised with this study is really that the user groups were poly-drug users. Without the test subjects only using MDMA, how can this be so conclusive? Especially since LSD and Marijuana were quite popular with both groups, drugs that are regarded (albiet subjectively) to fry / fuzzle the brain, although this is generally considered to be short term. We also know that heavy amphetamine use causes psychological problems. However, what this study also tried to show is that these side-effects found do not go away after stopping use. But this data is a bit sketchy to draw such a conclusion, since most of the former users had not even gone a year since last use. There is also a question about the control group of non-users, which were recruited like the rest, that is word of mouth. Surely demographics played a role into who came forward to do this? It is truly representative of ‘normal' people? Lastly, the groups of users and ex-users - how representative are they of the typical raver or clubber? Most of these would consider their use to be heavy. What does this data mean for the average e-user who might not take more that a pill a month? It seems difficult to extrapolate answers from this research.

Whilst there are these, and possibly more unanswered questions about this study, we cannot ignore the facts it presents, that is that this drug consumption had an effect on the ‘brain power' of those users. This is especially clear with the random letter generation where users generated fewer letters, more repeats and slipped up on the vowel exclusion. This test has been shown to place a continual strain on the ‘central executive' and is ‘relatively demanding of cognitive resources'.

However many problems can be found with this study, we have to take the important message that recreational drug use is not without any side effects, some of which may be long lasting. This study does give us a bit of an insight, however it would be more convincing to have all the corners covered and more conclusive results.

-editor
3 June 2000

 

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