To reach the conclusion, the study, which was led by Swansea University's head of psychology Professor Mark Blagrove, assessed the effects of ecstasy on story memory and skills learning.
In one of the tests, volunteers were asked to recall details of a short newspaper story about a fire on a farm. Those who had taken ecstasy two to three days before hearing about the article could only recall 83 per cent of the details that non-drug takers were able to recall.
"Importantly, the study ensured that the ecstasy users were obtaining as much sleep as the non-drug takers, and so this result is not due to lack of sleep or the drug-taking lifestyle," the Independent quoted Professor Blagrove, as saying.
The study, which was carried out on several groups, including people who do not take illegal drugs; people who take various drugs but don't take ecstasy; ecstasy users who had taken the drug two to three days before the first testing session; and ecstasy users who had not taken the drug for at least eight days before the first testing session, also looked at how well ecstasy users could learn a typing task.
Professor Blagrove said: "In contrast to the story memory task, the ecstasy users had no problems learning this skill. Consequently, it appears that ecstasy seems to affect memory for facts rather than the learning of new motor skills.
"The study means that certain aspects of work and employment will be a problem for frequent ecstasy users. Although they may be able to learn simple skills, the more complicated learning of knowledge, as a series of facts, is harmed by ecstasy."
The research found that the drug's active chemical, MDMA, affects the brain chemical serotonin, which aids the transmission of messages between nerve cells.
It is reckoned that serotonin plays an important role in how the human body processes thoughts and regulates sleeping and eating patterns.