title: Electrophysiological indices of altered working memory processes in long-term ecstasy users.
abstract: OBJECTIVE
  The aim of this study was to determine the effect of light long-term ecstasy consumption on verbal short-term and working memory and to identify the cognitive processes contributing to task performance.
  
  
  METHODS
  Electroencephalogram was recorded while ecstasy users (N = 11), polydrug users (N = 13), and non-users (N = 13) completed forward and backward serial recognition tasks designed to engage verbal short-term memory and verbal working memory, respectively.
  
  
  RESULTS
  All three groups displayed significantly lower digit-backward span than digit-forward span with ecstasy users displaying the greatest difference. The parietally distributed P3b was significantly smaller in the digits backward task than in the digits forward task in non-ecstasy-using controls. Ecstasy users did not show the reduced P3b component in the backward task that was seen in both non-ecstasy-using control groups.
  
  
  CONCLUSIONS
  Ecstasy users' performance was suppressed more by the concurrent processing demands of the working memory task than that of the non-ecstasy-using controls. Non-ecstasy-using controls showed differential event-related potential wave forms in the short-term and working memory tasks, and this pattern was not seen in the ecstasy users. This is consistent with a reduction in the cognitive resources allocated to processing in working memory in ecstasy users.
authors.affiliation: School of Psychology, University of Western Australia, Western Australia, Australia. clairenulsen@graduate.uwa.edu.au
authors.forename: Claire
authors.initials: C
authors.lastname: Nulsen
authors.forename: Allison
authors.initials: A
authors.lastname: Fox
authors.forename: Geoff
authors.initials: G
authors.lastname: Hammond
mesh_terms: D000328:Adult; D003071:Cognition / Q000187:drug effects; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects*; D005260:Female; D006213:Hallucinogens / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000009:adverse effects*; D019966:Substance-Related Disorders / Q000150:complications; D055815:Young Adult
chemical_list: D006213:Hallucinogens; D018817:N-Methyl-3,4-methylenedioxyamphetamine