title: The cyclic psychedelics.
mesh_terms: D004739:England; D006213:Hallucinogens / Q000266:history*; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D008093:Literature, Modern; D009892:Opium / Q000266:history; D019966:Substance-Related Disorders / Q000266:history*
chemical_list: D006213:Hallucinogens; D009892:Opium