College on Problems of Drug Dependence
Date: Wednesday, 6/21/2006
Time: 2:15 PM
Does a single or low dose of ecstasy affect memory brain function?
G. Jager(1), M. Win(2), J. van Ree(1), W. van den Brink(2), R. Kahn(1) and N. Ramsey(1)
(1) Rudolf Magnus Institute of Neuroscience, Utrecht, Netherlands and (2) Academic Medical Center, Amsterdam, Netherlands
Background It is debated whether a single or low dose of ecstasy is neurotoxic to human brain function. In this study we prospectively investigated the non-acute effects of a single or low dose of ecstasy on associative memory function in ecstasy-naive volunteers, using fMRI. Methods 50 Subjects, 26 novice ecstasy users and 24 persistent ecstasy-naive matched controls were assessed twice: first at baseline (all subjects still ecstasy-naive) and second after a period of first ecstasy use (mean 2.73.8 tablets) or a comparable follow-up period in the persistent ecstasy-naive group. Time since last ecstasy use in the novice users was ? 2 weeks. Associative memory function (performance and brain activity) was examined by fMRI. Results Both novice users and persistent ecstasy-nave controls performed normally during baseline and follow-up. Based on a brain activity map of the whole group, 9 regions of interest were defined in the prefrontal cortex, the parahippocampal area, the occipital gyrus and the anterior cingulate cortex. GLM analysis revealed no significant differences in activity between groups across baseline and follow-up scanning. Within the group of novice ecstasy users no correlations were found between the number of ecstasy tablets and memory performance or brain activity. Conclusion No sustained effects were found of low dose ecstasy use on associative memory function. In a previous study with heavy ecstasy users, we demonstrated clear non-acute impairments in associative learning and abnormal brain activity, using the same fMRI-paradigm (in preparation). Therefore, the current lack of findings cannot be explained by insensitivity of the method used. Apparently, low dose ecstasy use in otherwise healthy volunteers has no sustained effect on associative memory brain function. It should be noted, however, that small but significant effects on verbal memory were observed using a cognitive task in the same study population (Schilt et al, submitted). As of yet it is not clear how this apparent discrepancy should be interpreted.