The Effect of Singular Nonverbal Behaviours of Experimenters on Pain Reports

Hojjat Daniali,1 Mollie A Ruben,2 Per M Aslaksen,3 Charlotte Fiskum,1 Ted J Kaptchuk,4 Magne A Flaten1 1Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway; 2Department of Psychology, University of Rhode Island, Kingston, RI, USA; 3Department of Psychology, UiT The Arctic University of Norway, Tromsø, Norway; 4Program in Placebo Studies, Beth Israel Deaconess Medical Center/ Harvard Medical School, Boston, MA, USACorrespondence: Hojjat Daniali, Department of Psychology, Norwegian University of Science and Technology, Trondheim, NO-7491, Norway, Email [email protected]: Studies suggest facial expressions of caregivers may be important in placebo effects; however, this has not been systematically tested. This experiment investigated the effects of caregivers’ singular positive nonverbal behaviours (NBs) on pain reports.Methods: Fifty-one males and 53 females (total of 104) participants were randomized to four groups that were displayed positive facial expressions, tone of voice, body movement, or neutral NBs of videotaped experimenters. Subjective reports of pain, stress, arousal, and cardiac activity were obtained in a pre-test, a conditioning phase, and at a post-test. Four minutes of heat pain was induced in each test, and a placebo cream was administered before the conditioning and post-test in all groups.Results: There were no differences between the NB groups in the reduced pain. Males had larger reduction in pain in the post-test, and females had lower arousal than the opposite sex. During the conditioning, females had larger reduction in pain ie, unconditioned pain response (UPR). In females, the UPR predicted the reinforced expectation ie, increase in expectations from conditioning to post-test, and fear of minor pain negatively predicted both the UPR and reinforced expectation.Discussion: Singular NBs of caregiver were weak to enhance placebo effects. Females had lower pain during conditioning, and the UPR amplitude in females was associated with positive expectations. Moreover, for females, fear of minor pain weakened the UPR and expectations of cream.Conclusion: No NB of caregivers is more effective in reducing pain. Caregivers’ NBs are less effective when displayed individually. Males and females may be different in underlying mechanisms of placebo effects.Keywords: placebo effects, subtle factors, nonverbal behaviours, heat pain, experimenter effects, pain repor

Interaction between expectancies and drug effects: an experimental investigation of placebo analgesia with caffeine as an active placebo

In a randomised placebo-controlled clinical trial it is assumed that psychosocial effects of the treatment, regression to the mean and spontaneous remission are identical in the drug and placebo group. Consequently, any difference between the groups can be ascribed to the pharmacological effects. Previous studies suggest that side effects of drugs can enhance expectancies of treatment effects in the drug group compared to the placebo group, and thereby increase placebo responses in the drug group compared to the placebo group. The hypothesis that side effects of drugs can enhance expectancies and placebo responses was tested. Painful laser stimuli were delivered to 20 healthy subjects before and after administration of a drink with 0 or 4 mg/kg caffeine. The drink was administered either with information that it contained a painkiller or that it was a placebo. Laser-evoked potentials and reports of pain, expectancy, arousal and stress were measured. Results Four milligrammes per kilogramme of caffeine reduced pain. Information that a painkiller was administered increased the analgesic effect of caffeine compared to caffeine administered with no drug information. This effect was mediated by expectancies. Information and expectancies had no effect on pain intensity when 0 mg/kg was administered. The analgesic effect of caffeine was increased by information that a painkiller was administered. This was due to an interaction of the pharmacological action of the drug and expectancies. Hence, psychosocial effects accompanying a treatment can differ when an active drug is administered compared to a placebo

The Fear of Pain Questionnaire-III and the Fear of Pain Questionnaire-Short Form: a confirmatory factor analysis

Sara M Vambheim,1 Peter Solvoll Lyby,1,2 Per M Aslaksen,1 Magne Arve Flaten,3 Ole Åsli,1 Laila M Martinussen4 1Department of Psychology, UiT, The Arctic University of Norway, Tromsø; 2CatoSenteret Rehabilitation Center, Son; 3Department of Psychology, NTNU, The Norwegian University of Science and Technology, Trondheim, Norway; 4Management Engineering, DTU, Technical University of Denmark, Lyngby, Denmark Background: The Fear of Pain Questionnaire-III (FPQ-III) is a widely used instrument to assess the fear of pain (FOP) in clinical and nonclinical samples. The FPQ-III has 30 items and is divided into three subscales: Severe Pain, Minor Pain and Medical Pain. Due to findings of poor fit of the original three-factor FPQ-III model, the Fear of Pain Questionnaire-Short Form (FPQ-SF) four-factor model has been suggested as an alternative. The FPQ-SF is a revised version of the FPQ-III, reduced to 20 items and subdivided into four subscales: Severe Pain, Minor Pain, Injection Pain and Dental Pain. Aims and methods: The purpose of the study was to investigate the model fit, reliability and validity of the FPQ-III and the FPQ-SF in a Norwegian nonclinical sample, using confirmatory factor analysis (CFA). The second aim was to explore the model fit of the two scales in male and female subgroups separately, since previous studies have uncovered differences in how well the questionnaires measure FOP across sex; thus, the questionnaires might not be sex neutral. It has been argued that the FPQ-SF model is better because of the higher fit to the data across sex. To explore model fit across sex within the questionnaires, the model fit, validity and reliability were compared across sex using CFA. Results: The results revealed that both models’ original factor structures had poor fit. However, the FPQ-SF had a better fit overall, compared to the FPQ-III. The model fit of the two models differed across sex, with better fit for males on the FPQ-III and for females on the FPQ-SF. Conclusion: The FPQ-SF is a better questionnaire than the FPQ-III for measurement of FOP in Norwegian samples and across sex subgroups. However, the FPQ-III is a better questionnaire for males than for females, whereas the FPQ-SF is a better questionnaire for females than for males. The findings are discussed and directions for future investigations outlined. Keywords: fear of pain, FPQ-III, FPQ-SF, confirmatory factor analysis, pain, se