Regular Recreational Drug Use Affects Memory

Have you ever forgotten to post an important letter or let an appointment slip your mind? A new study from UK researchers suggests that for those who regularly use ecstasy or other recreational drugs, this kind of memory lapse is more common. Their research, which uncovered potential links between memory deficits and cocaine for the first time, appears in the Journal of Psychopharmacology, published by SAGE.

Florentia Hadjiefthyvoulou, John Fisk, and Nikola Bridges from the University of Central Lancashire and Catharine Montgomery from Liverpool John Moores University wanted to delve deeper into the link between deficits in prospective memory (remembering to remember, or remembering to perform an intended action) and drug use.

The new research into prospective memory expands on previous studies, which have shown that ecstasy or polydrug users are impaired in performing a number of cognitive tasks, including verbal and spatial exercises. A team led by Fisk also published evidence in 2005 that those using ecstasy perform worse in deductive reasoning, too.

Prospective memory tasks can be either time or event based, which means that the external trigger to remember could be in response to an event, or because it is time to do something. The distinction is important because these memory tasks use somewhat different brain processes.

The researchers recruited 42 ecstasy/polydrug users (14 males, 28 females) and 31 non-users (5 males, 26 females) for the study – all were students. The students were quizzed about their drug habits (including tobacco, cannabis and alcohol), and given questionnaires to assess their everyday memory, cognitive failures and prospective and retrospective memory. They were then given a number of lab-based memory tests, including some that required students to remember something several weeks later. The results showed that recreational drugs such as ecstasy, or the regular use of several drugs, affect users' memory functions, even when tests are controlled for cannabis, tobacco or alcohol use. According to Fisk, memory deficits were evident in both lab-based and self-reported measurements of subjects' prospective memory.

The results also suggested that ecstasy/polydrug users "possess some self awareness of their memory lapses."

The authors say that although ecstasy/polydrug users as a whole are aware of their memory problems they may be uncertain as to which illicit drug is behind the defects they perceive. "The present results suggest that these deficits are likely to be real rather than imagined and are evident in both time- and event-based prospective memory contexts," Fisk says.