Back to Basics - Effects, Narratives and Routes of Administration of Open-label Placebo

Study Overview
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Brief Summary
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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.

Detailed Description
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The current project will consist of one experimental study and one qualitative study: 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; 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.

Official Title
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Back to Basics - Effects, Narratives and Routes of Administration of Open-label Placebo

Conditions
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Placebo Effect, Pain, Expectancy

Intervention / Treatment
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* Other: open-label placebo
* Other: deceptive placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male and female adults aged 18-65 Healthy by self-report statement, thus no known current or chronic somatic diseases or psychiatric disorders Right-handedness (Oldfield, 1971), Willing to participate in study Exclusion Criteria: Medicine or Psychology Students Any acute or chronic disease (chronic pain, hypertension, heart disease, renal disease, liver disease, diabetes) as well as skin pathologies, neuropathies or nerve entrapment symptoms, sensory abnormalities affecting the tactile or thermal modality Current medications (psychoactive medication, narcotics, intake of analgesics) or being currently in psychological or psychiatric treatment Insufficient German language skills to understand the instructions Previous participation in studies using pain assessment (threshold and tolerance) with Peltier Devices Daily consumption of more than three alcoholic standard beverages per day (a standard alcoholic beverage is defined as either 3dl beer or 1 dl wine or 2cl spirits) Current or regular drug consumption (THC, cocaine, heroin, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: open-label placebo<br>Participants (N=40) will have the information that they are receiving an inert cream (i.e. placebo). Placebo will be described as an inert or inactive cream, with no medication in it. Additionally, participants will be told that placebo has been shown in rigorous clinical testing to produce significant mind-body self-healing processes. The placebo administration will be combined with the following scientific rationale/verbal suggestion: (a) placebos are effective analgesics, (b) classical conditioning as a possible mechanism of this effect, (c) compliance is important for outcome and (d) positive expectations increase placebo effects, but are not necessary. | Other: open-label placebo<br>* Placebo Cream, openly described as Placebo<br>|
| Sham Comparator: deceptive placebo<br>Participants (N=40) will have the information that they are receiving an analgesic cream (Antidolor, containing Lidocain), while in fact they will receive an inert cream, only. Antidolor will be described as an analgesic cream. | Other: deceptive placebo<br>* Placebo Cream, described as Voltaren, containing Diclofenac<br>|
| Placebo Comparator: control group<br>Participants (N=40) will have the information that they are receiving an inert control cream. | Other: open-label placebo<br>* Placebo Cream, openly described as Placebo<br>|
| No Intervention: no treatment group<br>Participants (N=40) will be told that they are in the no treatment group and that they will not receive an analgesic cream. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| subjective intensity and unpleasantness ratings of heat pain tolerance | Visual Analogue Scale (VAS) | 2 hours | 
| objective heat pain tolerance | Temperatures | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Expectancy of Relief Scale (ERS; Erwartungsfragebogen) |  | 2 hours | 
| Credibility and Effectiveness of the placebo analgesia expectation; adapted Version of the Context Model Questionnaire; Kontextmodellfragebogen (KMF) |  | 2 hours | 
| multidimensional sensitivities questionnaire (Mehrdimensionaler Befindlichkeitsfragebogen (MDBF)) |  | 2 hours | 
| sociodemographic questionnaire (Soziodemographischer Fragebogen (SDD)) |  | 2 hours | 
| Revised Life Orientation Test (LOT-R) |  | 2 hours | 
| NEO five-factor inventory (NEO-FFI) |  | 2 hours | 
| questionnaire on competence and locus of control (Fragebogen zu Kompetenz- und Kontrollüberzeugungen (FKK)) |  | 2 hours | 
| Anxiety and Depression Scale (HADS-D) |  | 2 hours | 
| Beliefs in holistic health and holistic treatments; Complementary and Alternative Medicine Beliefs Intentory (CAMBI) |  | 2 hours | 
| Desire for Relief Scale (DRS) |  | 2 hours | 
| subjective intensity and unpleasantness ratings of heat pain threshold | Visual Analogue Scale (VAS) | 2 hours | 
| objective heat pain threshold | Temperatures | 2 hours |