title: Hypnotic activity of placebo in relation to severity of insomnia: a quantitative evaluation.
mesh_terms: D000328:Adult; D000368:Aged; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010634:Phenobarbital / Q000627:therapeutic use*; D010919:Placebos / Q000627:therapeutic use*; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy*
chemical_list: D006993:Hypnotics and Sedatives; D010919:Placebos; D010634:Phenobarbital