title: The differential effects of ecstasy/polydrug use on executive components: shifting, inhibition, updating and access to semantic memory.
abstract: OBJECTIVE
  Recent theoretical models suggest that the central executive may not be a unified structure. The present study explored the nature of central executive deficits in ecstasy users.
  
  
  METHODS
  In study 1, 27 ecstasy users and 34 non-users were assessed using tasks to tap memory updating (computation span; letter updating) and access to long-term memory (a semantic fluency test and the Chicago Word Fluency Test). In study 2, 51 ecstasy users and 42 non-users completed tasks that assess mental set switching (number/letter and plus/minus) and inhibition (random letter generation).
  
  
  RESULTS
  MANOVA revealed that ecstasy users performed worse on both tasks used to assess memory updating and on tasks to assess access to long-term memory (C- and S-letter fluency). However, notwithstanding the significant ecstasy group-related effects, indices of cocaine and cannabis use were also significantly correlated with most of the executive measures. Unexpectedly, in study 2, ecstasy users performed significantly better on the inhibition task, producing more letters than non-users. No group differences were observed on the switching tasks. Correlations between indices of ecstasy use and number of letters produced were significant.
  
  
  CONCLUSIONS
  The present study provides further support for ecstasy/polydrug-related deficits in memory updating and in access to long-term memory. The surplus evident on the inhibition task should be treated with some caution, as this was limited to a single measure and has not been supported by our previous work.
authors: School of Psychology, Liverpool John Moores University, Liverpool, L3 2ET, UK.
authors: Catharine
authors: C
authors: Montgomery
authors: John E
authors: JE
authors: Fisk
authors: Russell
authors: R
authors: Newcombe
authors: Phillip N
authors: PN
authors: Murphy
mesh_terms: D000328:Adult; D003071:Cognition / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D019966:Substance-Related Disorders / Q000523:psychology*
chemical_list: D018817:N-Methyl-3,4-methylenedioxyamphetamine