Chronic ecstasy (MDMA) use is associated with deficits in task-switching but not inhibition or memory updating executive functions

The study aimed to establish whether prior ecstasy (MDMA) use caused impairments in tasks which targeted specific executive functions and whether the magnitude of impairments were correlated with the level of drug use. Subjects who had used ecstasy and cannabis (N = 33), subjects who had used cannabis but not ecstasy (N = 17) and subjects who had used neither drug (N = 18) were tested on a standard and modified form of the Stroop Colour-Word test to look for impairments in inhibition and in task-switching, respectively. A Keep Track Task was used to assess working memory updating ability. Ecstasy users, but neither of the other groups were significantly impaired (slower reaction times) on the task-switching version of the Stroop test (p < .05), but not on the standard version or on the Keep Track Task. Regression analysis showed a significant correlation between level of lifetime ecstasy use and magnitude of the switching-impairment. The findings are interpreted in line with recent theoretical views which regard executive function as composed of multiple independent cognitive components such as inhibition, switching and memory updating, only some of which may be affected by drug use or other factors.