title: ERP evidence suggests executive dysfunction in ecstasy polydrug users.
abstract: BACKGROUND
  Deficits in executive functions such as access to semantic/long-term memory have been shown in ecstasy users in previous research. Equally, there have been many reports of equivocal findings in this area. The current study sought to further investigate behavioural and electro-physiological measures of this executive function in ecstasy users.
  
  
  METHODS
  Twenty ecstasy-polydrug users, 20 non-ecstasy-polydrug users and 20 drug-naïve controls were recruited. Participants completed background questionnaires about their drug use, sleep quality, fluid intelligence and mood state. Each individual also completed a semantic retrieval task whilst 64 channel Electroencephalography (EEG) measures were recorded.
  
  
  RESULTS
  Analysis of Variance (ANOVA) revealed no between-group differences in behavioural performance on the task. Mixed ANOVA on event-related potential (ERP) components P2, N2 and P3 revealed significant between-group differences in the N2 component. Subsequent exploratory univariate ANOVAs on the N2 component revealed marginally significant between-group differences, generally showing greater negativity at occipito-parietal electrodes in ecstasy users compared to drug-naïve controls. Despite absence of behavioural differences, differences in N2 magnitude are evidence of abnormal executive functioning in ecstasy-polydrug users.
authors.affiliation: School of Natural Sciences and Psychology, LJMU, Tom Reilly Building, Byrom St, Liverpool L3 3AF, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Roberts
authors.forename: S H
authors.initials: SH
authors.lastname: Fairclough
authors.forename: J E
authors.initials: JE
authors.lastname: Fisk
authors.forename: F
authors.initials: F
authors.lastname: Tames
authors.forename: C
authors.initials: C
authors.lastname: Montgomery
mesh_terms: D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D016022:Case-Control Studies; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects*; D056344:Executive Function / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000633:toxicity*; D012890:Sleep / Q000187:drug effects; D019966:Substance-Related Disorders / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D018817:N-Methyl-3,4-methylenedioxyamphetamine