title: Neural mechanisms of working memory in ecstasy (MDMA) users who continue or discontinue ecstasy and amphetamine use: evidence from an 18-month longitudinal functional magnetic resonance imaging study.
abstract: BACKGROUND
  Working memory processing in ecstasy (3,4-methylenedioxymethamphetamine) users is associated with neural alterations as measured by functional magnetic resonance imaging. Here, we examined whether cortical activation patterns change after prolonged periods of continued use or abstinence from ecstasy and amphetamine.
  
  
  METHODS
  We used an n-back task and functional magnetic resonance imaging in 17 ecstasy users at baseline (t(1)) and after 18 months (t(2)). Based on the reported drug use at t(2) we separated subjects with continued ecstasy and amphetamine use from subjects reporting abstinence during the follow-up period (n = 9 and n = 8, respectively).
  
  
  RESULTS
  At baseline both groups had similar task performance and similar cortical activation patterns. Task performance remained unchanged in both groups. Furthermore, there were no detectable functional magnetic resonance imaging signal changes from t(1) to t(2) in the follow-up abstinent group. However, the continuing users showed a dose-dependent increased parietal activation for the 2-back task after the follow-up period.
  
  
  CONCLUSIONS
  Our data suggest that ecstasy use, particularly in high doses, is associated with greater parietal activation during working memory performance. An altered activation pattern might appear before changes in cognitive performance become apparent and, hence, may reflect an early stage of neuronal injury from the neurotoxic drug ecstasy.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Cologne Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Daumann
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischermann
authors.forename: Karsten
authors.initials: K
authors.lastname: Heekeren
authors.forename: Armin
authors.initials: A
authors.lastname: Thron
authors.forename: Euphrosyne
authors.initials: E
authors.lastname: Gouzoulis-Mayfrank
mesh_terms: D000328:Adult; D000661:Amphetamine / Q000009:adverse effects*; D002188:Cannabis / Q000009:adverse effects; D000697:Central Nervous System Stimulants / Q000009:adverse effects; D002540:Cerebral Cortex / Q000098:blood supply / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006213:Hallucinogens / Q000009:adverse effects; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000009:adverse effects*; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011930:Reaction Time / Q000187:drug effects; D012044:Regression Analysis; D019966:Substance-Related Disorders / Q000503:physiopathology*
chemical_list: D000697:Central Nervous System Stimulants; D006213:Hallucinogens; D000661:Amphetamine; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D010100:Oxygen