title: Altered visual perception in long-term ecstasy (MDMA) users.
abstract: BACKGROUND
  The present study investigated the long-term consequences of ecstasy use on visual processes thought to reflect serotonergic functions in the occipital lobe. Evidence indicates that the main psychoactive ingredient in ecstasy (methylendioxymethamphetamine) causes long-term changes to the serotonin system in human users. Previous research has found that amphetamine-abstinent ecstasy users have disrupted visual processing in the occipital lobe which relies on serotonin, with researchers concluding that ecstasy broadens orientation tuning bandwidths. However, other processes may have accounted for these results.
  
  
  OBJECTIVE
  The aim of the present research was to determine if amphetamine-abstinent ecstasy users have changes in occipital lobe functioning, as revealed by two studies: a masking study that directly measured the width of orientation tuning bandwidths and a contour integration task that measured the strength of long-range connections in the visual cortex of drug users compared to controls.
  
  
  METHODS
  Participants were compared on the width of orientation tuning bandwidths (26 controls, 12 ecstasy users, 10 ecstasy + amphetamine users) and the strength of long-range connections (38 controls, 15 ecstasy user, 12 ecstasy + amphetamine users) in the occipital lobe.
  
  
  RESULTS
  Amphetamine-abstinent ecstasy users had significantly broader orientation tuning bandwidths than controls and significantly lower contour detection thresholds (CDTs), indicating worse performance on the task, than both controls and ecstasy + amphetamine users.
  
  
  CONCLUSIONS
  These results extend on previous research, which is consistent with the proposal that ecstasy may damage the serotonin system, resulting in behavioral changes on tests of visual perception processes which are thought to reflect serotonergic functions in the occipital lobe.
authors.affiliation: Research School of Psychology, Australian National University, Building 39, Canberra, ACT 0200, Australia. claire.white@anu.edu.au
authors.forename: Claire
authors.initials: C
authors.lastname: White
authors.forename: John
authors.initials: J
authors.lastname: Brown
authors.forename: Mark
authors.initials: M
authors.lastname: Edwards
mesh_terms: D000328:Adult; D019969:Amphetamine-Related Disorders / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000008:administration & dosage* / Q000009:adverse effects; D009778:Occipital Lobe / Q000187:drug effects* / Q000473:pathology*; D010775:Photic Stimulation / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors; D014796:Visual Perception / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
chemical_list: D018817:N-Methyl-3,4-methylenedioxyamphetamine