title: Cannabis laws 'threaten validity of trials'.
authors.forename: E
authors.initials: E
authors.lastname: Masood
mesh_terms: D002188:Cannabis; D002986:Clinical Trials as Topic; D004335:Drug and Narcotic Control; D006801:Humans; D008385:Marijuana Smoking; D009103:Multiple Sclerosis / Q000188:drug therapy*; D010946:Plants, Medicinal; D006113:United Kingdom