Open AccessEffects of Ginger and Expectations on Symptoms of Nausea in a Balanced Placebo Design
Author(s) -
Katja Weimer,
Joerg Schulte,
Annamaria Maichle,
Eric R. Muth,
Jenna L. Scisco,
Bjoern Horing,
Paul Enck,
Sibylle Klosterhalfen
Publication year - 2012
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0049031
Subject(s) - placebo , nausea , antiemetic , medicine , psychosocial , psychology , anesthesia , psychiatry , alternative medicine , pathology
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. Conclusion The effects of an antiemetic drug and provided information interact with psychosocial variables of participants and experimenters in reports of nausea.