People who take ecstasy are at risk of impairing their long-term memory, according to research.
Scientists said those who also take cannabis face a "double whammy" of suffering short-term memory loss as well.
An international survey found regular ecstasy users were 23 per cent more likely to report problems with remembering things than non-users.
Researchers said that until now little had been known about the impact of ecstasy and other drug use on memory. The study found that those who regularly took ecstasy were more likely to suffer from mainly long-term memory difficulties.
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 ecstasy users were more likely to use other drugs including cannabis the researchers said they were vulnerable to a "time bomb" of memory afflictions in later life.
Results of the study are published in the current edition of the Journal of Psychopharmacology.
Hundreds of users and non-drug users took part in the web-based survey which questioned people from Britain, Europe, the United States, and Australia.
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 on to somebody.
PA