Acute dose of MDMA (75 mg) impairs spatial memory for location but leaves contextual processing of visuospatial information unaffected.
BACKGROUND
Research concerning spatial memory in 3,4-methylenedioxymethamphetamine (MDMA) users has presented conflicting results showing either the presence or absence of spatial memory deficits. Two factors may have confounded results in abstinent users: memory task characteristics and polydrug use.


OBJECTIVE
The present study aims to assess whether a single dose of MDMA affects spatial memory performance during intoxication and withdrawal phase and whether spatial memory performance after MDMA is task dependent.


METHODS
Eighteen recreational MDMA users participated in a double-blind, placebo-controlled, three-way crossover design. They were treated with placebo, MDMA 75 mg, and methylphenidate 20 mg. Memory tests were conducted between 1.5 and 2 h (intoxication phase) and between 25.5 and 26 h (withdrawal phase) post-dosing. Two spatial memory tasks of varying complexity were used that required either storage of stimulus location alone (spatial memory task) or memory for location as well as processing of content or contextual information (change blindness task).


RESULTS
After a single dose of MDMA, the subjects made larger localization errors and responded faster compared to placebo in the simple spatial memory task during intoxication phase. Inaccuracy was not due to increased response speed, as determined by regression analysis. Performance in the change blindness task was not affected by MDMA. Methylphenidate did not affect performance on any of the tasks.


CONCLUSIONS
It is concluded that a single dose of MDMA impairs spatial memory for location but leaves processing of contextual information intact.
Kuypers
Kim P C
KP
Experimental Psychopharmacology Unit, Department of Neurocognition, Faculty of Psychology, Maastricht University, Maastricht, The Netherlands. k.kuypers@psychology.unimaas.nl
Ramaekers
Johannes G
JG
D000328:Adult; D000704:Analysis of Variance; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006213:Hallucinogens / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008568:Memory / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D013028:Space Perception / Q000187:drug effects*
D006213:Hallucinogens; D018817:N-Methyl-3,4-methylenedioxyamphetamine