title: Cannabis and psychosis: two kinds of limitations which attach to epidemiological research.
authors.forename: David M
authors.initials: DM
authors.lastname: Fergusson
mesh_terms: D002188:Cannabis / Q000009:adverse effects*; D006801:Humans; D008137:Longitudinal Studies; D008385:Marijuana Smoking / Q000009:adverse effects*; D011605:Psychoses, Substance-Induced / Q000453:epidemiology*