title: Importance of psychiatric confounding in non-randomized studies of heavy ecstasy users.
authors.forename: T S
authors.initials: TS
authors.lastname: Krebs
authors.forename: P-Ø
authors.initials: PØ
authors.lastname: Johansen
authors.forename: L
authors.initials: L
authors.lastname: Jerome
authors.forename: J H
authors.initials: JH
authors.lastname: Halpern
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects; D000437:Alcoholism / Q000453:epidemiology; D019969:Amphetamine-Related Disorders / Q000453:epidemiology*; D015982:Bias; D003072:Cognition Disorders / Q000139:chemically induced / Q000453:epidemiology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D006213:Hallucinogens / Q000633:toxicity; D006801:Humans; D013287:Illicit Drugs / Q000633:toxicity; D001523:Mental Disorders / Q000453:epidemiology*; D011939:Mental Recall / Q000187:drug effects; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000633:toxicity; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011594:Psychometrics; D012189:Retrospective Studies; D019966:Substance-Related Disorders / Q000453:epidemiology; D014706:Verbal Learning / Q000187:drug effects
chemical_list: D006213:Hallucinogens; D013287:Illicit Drugs; D018817:N-Methyl-3,4-methylenedioxyamphetamine