Gender and the nocebo response following conditioning and expectancy.
OBJECTIVE
To investigate the role of Pavlovian conditioning and expectancy and of gender on the nocebo effects.


METHODS
Conditioning experiment: Forty-eight healthy male and female volunteers were investigated for 3 days using a standard rotation procedure. Subjects in the experimental group received a salient oral stimulus prior to rotation; subjects in the control group received the stimulus 12 h after rotations on Days 1 and 2; on Day 3, all subjects received the stimulus prior to rotation. Expectancy experiment: Another 48 healthy subjects were rotated 5 x 1 min once only. All subjects received the same oral stimulus immediately prior to rotation; subjects in the experimental group were told that the symptoms might worsen with the stimulus; controls did not receive additional information. In both experiments, symptom rating (SR) and rotation tolerance (RT) were determined.


RESULTS
Conditioning significantly reduced RT (P=.015) and increased SR (P=.024). For both RT and SR, a significant "day x group x gender" effect was found (P=.044; SR: P=.011) indicating that conditioning was more effective in women. Expectancies lowered RT (P=.085) without affecting SR. There was a significant "rotation x gender" interaction on RT (P=.005) indicating that the expectancy was more effective in men.


CONCLUSIONS
Women responded stronger to conditioning while men responded to expectancies, but to a lesser degree. It needs to be determined whether this is restricted to nausea-specific conditions or can be generalized across clinical and experimental conditions.
Klosterhalfen
Sibylle
S
Department of Internal Medicine VI, University Hospital Tübingen, Tübingen, Germany.
Kellermann
Sandra
S
Braun
Silke
S
Kowalski
Axel
A
Schrauth
Markus
M
Zipfel
Stephan
S
Enck
Paul
P
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D003214:Conditioning, Classical; D003213:Conditioning, Psychological; D005260:Female; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D009325:Nausea / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D009483:Neuropsychological Tests; D010919:Placebos / Q000009:adverse effects*; D011597:Psychomotor Performance; D012399:Rotation / Q000009:adverse effects*; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
D010919:Placebos