This piece from The Guardian (UK):
Ecstasy impairs memory, study shows
James Randerson, science correspondent
Tuesday June 5, 2007
Ecstasy can cause lasting damage to the human brain, even if the drug is only taken for a short time, according to new research. The memory of ecstasy users who were asked to remember lists of words was impaired, the study found.
Researchers compared the performance of the subjects before and after they first tried the drug and concluded that even low doses of the drug could have lasting effects on the brain.
The ideal experiment to investigate the effect of ecstasy on human memory would be to give the drug or a placebo to different participants at random. That would be unethical, so the next best thing would be to test non-drug users first, and then again if they decide to take the drug.
Research on animals has shown that ecstasy can cause long-lasting damage to neurons involved in processing serotonin, a chemical involved in controlling learning, memory, mood and other functions. In several studies a brain region called the hippocampus which is known to be involved in memory has shown up as being particularly badly affected.
A team led by Ben Schmand at the University of Amsterdam recruited 188 volunteers who had never tried the drug, but who said they would probably soon do so. The team tested their performance in a battery of psychological exercises, including tests of attention and memory.
Months later, the team went back to their volunteers and tested 58 who had since taken at least one ecstasy tablet. These subjects were matched against a similar number of controls of a similar age and history of drug use. On average, the subjects who had started to use the drug had taken around three pills in total.
Despite this low dosage, the researchers found a small but statistically significant drop in the volunteers' ability to remember words. This test involved reciting a list of 15 words and remembering the list 20 minutes later. Their performance in other tests was not hampered. "Our data indicate that low doses of ecstasy are associated with decreased verbal memory function, which is suggestive for ecstasy-induced neurotoxicity," the authors write in the journal Archives of General Psychiatry. "The main underlying factor seems to be a depletion of serotonin in ecstasy users, a depletion that might be reversible. Serotonin is involved in several cognitive functions, but might be especially relevant to learning and memory."