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

University Hospital Basel

Status: Completed

Conditions: Pain; Placebo Effect; Expectancy

Treatments: Other: open-label placebo; Other: deceptive placebo

Study type: Interventional

Funder types: Other

Identifiers

NCT02578420

EKNZ 2015-246

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 160 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

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.)

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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160 participants in 4 patient groups, including a placebo group

open-label placebo

Placebo Comparator group

Description:

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.

Treatment:

Other: open-label placebo

deceptive placebo

Sham Comparator group

Description:

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.

Treatment:

Other: deceptive placebo

control group

Placebo Comparator group

Description:

Participants (N=40) will have the information that they are receiving an inert control cream.

Treatment:

Other: open-label placebo

no treatment group

No Intervention group

Description:

Participants (N=40) will be told that they are in the "no treatment group" and that they will not receive an analgesic cream.