The study, which also surveyed non-drug users, found that those who regularly took ecstasy suffered from mainly long-term memory difficulties, and that they were 23 per cent more likely to report problems with remembering things than non-users.
The British research team, led by the University of Newcastle upon Tyne, also questioned volunteers about their use of other recreational drugs. It found those who regularly used cannabis reported up to 20 per cent more memory problems than non-users. Their short-term memory was mainly affected.
Because evidence has shown ecstasy users are likely to use other drugs, including cannabis, the researchers say they are vulnerable to a myriad of memory afflictions which may represent a 'time bomb' of cognitive problems for later life.
Results of the study are published in the current edition of the Journal of Psychopharmacology.
Use of ecstasy, otherwise known as 3,4-methylenedioxymethamphetamine, or MDMA, is on the increase, with up to two million tablets being consumed every weekend in the UK.
Until now, little has been known about the impact of ecstasy and other drug use on everyday and long-term memory.
Researchers from the Universities of Newcastle upon Tyne, Northumbria, Westminster, Teesside and East London surveyed drug users via a web-based questionnaire.
Volunteers were posed questions about their everyday and long-term memory and asked to rank the probability of scenarios such as finding a television story difficult to follow and forgetting to pass a message onto somebody.
The research team based their findings on responses from 763 participants but they also looked closely at a sub-group of 81 'typical' ecstasy users who had taken the drug at least ten times.
As well as analysing volunteers' responses to the memory tests, the team recorded the number of mistakes made when filling in the questionnaire.
They found the group of 'typical users' reported their long-term memory to be 14 per cent worse than the 480 people who had never taken ecstasy and 23 per cent worse than the 242 non-drug users.
In addition, this group made 21 per cent more errors on the questionnaire form than non-ecstasy users and 29 per cent more mistakes than people who did not take drugs at all.
Lead researcher Dr. Jacqui Rodgers, of Newcastle University, said: "We all know of cases where people have suffered acutely from the use of ecstasy, such as the teenager Leah Betts, but relatively little is known about the more subtle effects on the increasing number of regular users worldwide.
"Users may think that ecstasy is fun and that it feels fairly harmless at the time. However, our results show slight but measurable impairments to memory as a result of use, which is worrying.
"It's equally concerning that we don't really know what the long-term effects of ecstasy use will be, as it is still a poorly understood drug. The results indicate that users are potentially creating a time bomb of potential cognitive difficulties in later life.
"The findings also suggest that ecstasy users who take cannabis are suffering from a 'double whammy' where both their long-term and short-term memory is being impaired."
Dr. Rodgers, of the School of Neurology, Neurobiology & Psychiatry, added that the results could inform drug therapy techniques: "The findings may help drug services in the UK and elsewhere to explain the potential consequences of use so that people can make an informed decision as to whether to take ecstasy or not."
The study also found no significant differences between results from male and female participants.
Journal of Psychopharmacology