title: Effects of ginger and expectations on symptoms of nausea in a balanced placebo design.
abstract: OBJECTIVE
  Ginger effects on (experimental) nausea have been described, but also strong placebo effects and sex differences when nausea is involved. The "balanced placebo design" has been proposed to allow better separation of drug and placebo effects.
  
  
  METHODS
  Sixty-four healthy participants (32 women) were randomly assigned to receive an antiemetic ginger preparation or placebo, and half of each group was told to have received drug or placebo. They were exposed to 5×2 min body rotations to induce nausea. Subjective symptoms and behavioral (rotation tolerance, head movements) and physiological measures (electrogastrogram, cortisol) were recorded. Groups were balanced for sex of participants and experimenters.
  
  
  RESULTS
  Ginger and the information given did not affect any outcome measure, and previous sex differences could not be confirmed. Adding the experimenters revealed a significant four-factorial interaction on behavioral but not on subjective or physiological measures Men who received placebo responded to placebo information when provided by the male experimenter, and to ginger information when provided by the female experimenter. This effect was not significant in women.
  
  
  CONCLUSIONS
  The effects of an antiemetic drug and provided information interact with psychosocial variables of participants and experimenters in reports of nausea.
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Weimer
authors.forename: Jörg
authors.initials: J
authors.lastname: Schulte
authors.forename: Annamaria
authors.initials: A
authors.lastname: Maichle
authors.forename: Eric R
authors.initials: ER
authors.lastname: Muth
authors.forename: Jenna L
authors.initials: JL
authors.lastname: Scisco
authors.forename: Björn
authors.initials: B
authors.lastname: Horing
authors.forename: Paul
authors.initials: P
authors.lastname: Enck
authors.forename: Sibylle
authors.initials: S
authors.lastname: Klosterhalfen
mesh_terms: D000328:Adult; D000932:Antiemetics / Q000627:therapeutic use*; D005260:Female; D020939:Zingiber officinale / Q000737:chemistry*; D019416:Head Movements; D006801:Humans; D008297:Male; D009325:Nausea / Q000188:drug therapy*; D015990:Placebo Effect; D012399:Rotation; D013270:Stomach / Q000502:physiology; D013997:Time Factors; D055815:Young Adult
chemical_list: D000932:Antiemetics