Placebo Effects on Blood Pressure

Study Overview
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Brief Summary
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A relevant reduction of blood pressure (BP) in placebo-treated control groups is a phenomenon often observed in pharmacological studies of hypertension. This effect was shown to differ from spontaneous remission tendencies and regression to the mean effect by comparing placebo groups with untreated controls. However, it is not fully understood whether these effects are due to a global reaction of the autonomous nervous system (affecting the overall organ systems of the body) or a specific reaction (affecting the cardiovascular system only). We therefore aim to differentiate specific effects (reduction of blood pressure) from global effects (e.g. changes in electrodermal and gastric activity). In our study we aim to test the following hypotheses: Placebo administration leads to a significant changes of blood pressure compared with untreated controls. The direction of blood pressure change depends on the type of suggestion (either decrease or increase) This effect is specific for blood pressure; changes in electrodermal and gastric activity do not differ between groups. The placebo response can be enhanced by a prestige intervention (information about the suggested drug action given by doctor or in written form).

Official Title
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Physiological Effects of Placebo Interventions to Increase or Decrease Blood Pressure

Conditions
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Blood Pressure

Intervention / Treatment
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* Other: Placebo with BP dec (written form)
* Other: Placebo with BP dec (doctor)
* Other: Placebo with BP inc (written)
* Other: Placebo with BP inc (doctor)
* Other: Placebo info given (written)
* Other: Placebo info given (doc)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed consent Exclusion Criteria: Not meeting inclusion criteria Untreated hypertension (BP > 140/90) or hypotension(BP < 100/60) Severe systemic disorders (tumors, tbc, diabetes, asthma etc) Diseases with influence on cardiovascular or gastrointestinal system Pregnancy and lactation phase Body mass index > 30 Regular intake of drugs with influence on the autonomic nervous system Insufficient compliance Simultaneous participation in another trial

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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 |
| --- | --- |
| Experimental: 1<br> | Other: Placebo with BP dec (written form)<br>* Placebo administration with a blood pressure decrease suggestion. Information provided to subjects in written form.<br>|
| Experimental: 2<br> | Other: Placebo with BP dec (doctor)<br>* Placebo administration with a blood pressure decrease suggestion. Information provided to subjects by doctor.<br>|
| Experimental: 3<br> | Other: Placebo with BP inc (written)<br>* Placebo administration with a blood pressure increase suggestion. Information provided to subjects in written form.<br>|
| Experimental: 4<br> | Other: Placebo with BP inc (doctor)<br>* Placebo administration with a blood pressure increase suggestion. Information provided to subjects by doctor.<br>|
| No Intervention: 5<br> | Other: Placebo info given (written)<br>* Subject informed about receiving placebo. Information provided to subjects in written form.<br>|
| No Intervention: 6<br> | Other: Placebo info given (doc)<br>* Subject informed about receiving placebo. Information provided to subjects by doctor.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean arterial pressure |  | 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate |  | 60 minutes | 
| skin conductance level |  | 60 minutes | 
| gastric activity |  | 60 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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placebo effect, blood pressure, autonomic nervous system, prestige, basic research on physiological placebo effects