Trust Game and Placebo Response

Study Overview
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Brief Summary
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In the proposed study, investigators aim to investigate the role of interpersonal trust in the conditioned placebo analgesia process with healthy male subjects in a standardized experimental heat pain paradigm.

Official Title
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Trust Game and Placebo Response

Conditions
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Placebo Effect, Pain, Trust

Intervention / Treatment
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* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men: age between 18 and 40 years old 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: 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

Sexes Eligible for Study
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Male

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: Control<br>All participants will also be introduced to the control cream: This cream is a control cream. | Other: Placebo<br> <br> |
| Sham Comparator: Placebo<br>All participants will then be introduced to an analgesia expectation: This cream is a powerful pain killer, while receiving an inert cream. In this study participants will be told that they will receive a potent painkiller as well as a control cream. Making use of placebo cream is an established method to induce placebo expectations . Moreover, to increase the analgesic effect, heat pain stimuli intensity will be surreptitiously lowered for the placebo trials to a temperature corresponding to 30% of the VAS intensity and to 60% for the control trials. As the occurrence of a placebo response is highly dependent on expectations, the deceptive procedure described above is used in order to maximally enhance expectations and therefore placebo response. Participants will be debriefed after the completion of study participation. | Other: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual analogue scale (VAS) rating (Intensity + unpleasantness of pain) |  | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual analogue scale (VAS) rating (trust) |  | 2 hours | 
| State-Trait-Anxiety (STAI- X1) |  | 2 hours | 
| State Trait Anger Expression (STAXI) |  | 2 hours | 
| Questionnaire about expectations (Erwartungsfragebogen) |  | 2 hours | 
| Questionnaire about the investigator (Fragebogen zum Versuchsleiter |  | 2 hours | 
| sociodemographic questionnaire (Soziodemographischer Fragebogen (SES)) |  | 2 hours | 
| Questionnaire about Self-assessment of partnership binding (Bochumer Bindungsfragebogen - BoBi) |  | 2 hours | 
| State-Trait-Anxiety (STAI-X2 ) |  | 2 hours |