To date, very little is known about the mechanisms of open-label placebo treatment and there is a lack in highly controlled experimental designs. Therefore, the planned project will test well-established explanatory models of (deceptive) placebo, i.e., (1) expectancy, (2) meaning response, in an open-label placebo design, investigating their influence on placebo analgesia.
The current project will consist of one experimental study and one qualitative study: 1. the effects of open-label, and deceptive placebo administration on placebo analgesia will be directly compared when both groups have a comparable expectancy-inducing scientific rationale; 2. subjective meaning models will be assessed by comparing subjective narratives of the placebo effect in open-label and deceptive placebo groups in a nested qualitative study. The experimental study will be a randomized experiment with healthy subjects (N=120), and pain will be induced using a standardized heat pain paradigm (Medoc, Ramatishai, Israel; thermo-sensory analyzer (TSA)-II). Effects of the experimental conditions will be assessed both objectively (i.e. heat pain threshold and tolerance) and subjectively (i.e. subjective pain ratings, pain intensity and unpleasantness). Furthermore, investigators will randomly select 30 participants to take part in a nested qualitative study in order to qualitatively assess the meaning response by comparing subjective narratives of the placebo effect in the open-label and deceptive placebo groups, as well as in the control group.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
160
Placebo Cream, openly described as "Placebo"
Placebo Cream, described as "Voltaren, containing Diclofenac"
University of Basel
Basel, Switzerland
subjective intensity and unpleasantness ratings of heat pain tolerance
Visual Analogue Scale (VAS)
Time frame: 2 hours
objective heat pain tolerance
Temperatures
Time frame: 2 hours
Expectancy of Relief Scale (ERS; Erwartungsfragebogen)
Time frame: 2 hours
Credibility and Effectiveness of the placebo analgesia expectation; adapted Version of the Context Model Questionnaire; Kontextmodellfragebogen (KMF)
Time frame: 2 hours
multidimensional sensitivities questionnaire (Mehrdimensionaler Befindlichkeitsfragebogen (MDBF))
Time frame: 2 hours
sociodemographic questionnaire (Soziodemographischer Fragebogen (SDD))
Time frame: 2 hours
Revised Life Orientation Test (LOT-R)
Time frame: 2 hours
NEO five-factor inventory (NEO-FFI)
Time frame: 2 hours
questionnaire on competence and locus of control (Fragebogen zu Kompetenz- und Kontrollüberzeugungen (FKK))
Time frame: 2 hours
Anxiety and Depression Scale (HADS-D)
Time frame: 2 hours
Beliefs in holistic health and holistic treatments; Complementary and Alternative Medicine Beliefs Intentory (CAMBI)
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Time frame: 2 hours
Desire for Relief Scale (DRS)
Time frame: 2 hours
subjective intensity and unpleasantness ratings of heat pain threshold
Visual Analogue Scale (VAS)
Time frame: 2 hours
objective heat pain threshold
Temperatures
Time frame: 2 hours