Reducing Nocebo Effects on Pressure Pain

Summary

Nocebo effects are known to adversely affect the experience of various physical symptoms, such as pain and itch. Nocebo effects can be induced by associative learning mechanisms of classical conditioning. Furthermore, recent studies have shown that counterconditioning can successfully reduce nocebo effects, and to a larger extent than mere extinction, which suggests counterconditioning can be an innovative method for desensitization of symptoms. When using such procedures in clinical practice, deception of patients should be avoided as much as possible. The use of open-label procedures could provide a promising alternative. While previous studies have already shown that open-label placebos are effective, the effects of open-label counterconditioning and closed-label counterconditioning are not extensively investigated in comparison to other strategies, such as extinction, and not yet compared amongst each other. Before implementing such a procedure in clinical practice, it would be relevant to get an insight in the efficacy of both open- and closed-label counterconditioning in healthy participants as compared to extinction and to investigate whether open-label counterconditioning can be equally effective as closed-label counterconditioning. Furthermore, it would be relevant to study the induction and reduction of nocebo effects using a pain modality that mimics the type of pain that people suffering from several chronic pain conditions experience, such as pressure pain. The main aim of the current study is to investigate whether open- and closed-label counterconditioning are more effective in reducing nocebo effects than extinction. To this aim, it will be investigated whether open- and closed-label counterconditioning lead to stronger reductions in nocebo effects on pressure pain than (closed-label) extinction, and whether all three successfully reduce nocebo effects. Finally, it will be tested whether open- and closed label counterconditioning are comparable in effectivity.

Conditions

• Pain
• Hyperalgesia

Interventions

BEHAVIORAL

Closed-label nocebo conditioning

Conditioning consists of a learning and test phase. In the learning phase, a message indicating the sham activation of a Transcutaneous Electrical Nerve Stimulation (TENS) device (CS) will be repeatedly paired with a moderate intensity pressure pain stimulus, whereas a message indicating the deactivation of the sham device will be repeatedly paired with a slightly painful pressure pain stimulus. Participants will be given a verbal suggestion in line with the conditioning procedure (i.e. activation of the device will increase their pain). The testing phase is similar to the learning phase, but a slight pressure pain intensity is used for all trials, to test for a nocebo effect (i.e. to test whether participants score "TENS on" trials as more painful than "TENS off" trials).

BEHAVIORAL

Closed-label counterconditioning

Counterconditioning consists of a learning and test phase. In the learning phase, a message indicating the sham activation of the TENS device (CS) is now repeatedly paired with a non-painful intensity pressure pain stimulus, whereas a message indicating the sham deactivation of the TENS device will be repeatedly paired with a slightly painful pressure pain stimulus. Participants will be given a verbal suggestion in line with the counterconditioning procedure (i.e. activation of the device will reduce their pain). The testing phase is similar to the learning phase, but a slight pressure pain intensity is used for all trials, to test whether the nocebo effect is successfully reduced (i.e. to test whether participants no longer score "TENS on" trials as more painful than "TENS off" trials or even score "TENS on" trials as less painful).

BEHAVIORAL

Open-label counterconditioning

Counterconditioning consists of a learning and test phase. In the learning phase, a message indicating the sham activation of the TENS device (CS) is now repeatedly paired with a non-painful intensity pressure pain stimulus, whereas a message indicating the sham deactivation of the TENS device will be repeatedly paired with a slightly painful pressure pain stimulus. Participants will be given a open-label verbal suggestions in line with the counterconditioning procedure (i.e. they are told counterconditioning will be used to reduce nocebo effects and they are told the device is sham, but that their pain will still be influenced because of the placebo effect). The testing phase is similar to the learning phase, but a slight pressure pain intensity is used for all trials, to test whether the nocebo effect is successfully reduced (i.e. to test whether participants no longer score "TENS on" trials as more painful than "TENS off" trials or even score "TENS on" trials as less painful).

BEHAVIORAL

Closed-label extinction

Extinction consists of a learning and test phase. In the learning phase, slightly painful stimuli are used for all trials. During the testing phase, again a slight pressure pain intensity is used for all trials, to test whether the nocebo effect is successfully reduced (i.e. to test whether participants no longer score "TENS on" trials as more painful than "TENS off" trials).

Sponsors & Collaborators

• Leiden University

  lead OTHER

Principal Investigators

• Andrea Evers, Prof · Leiden University

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-03-23

Primary Completion

2022-04-05

Completion

2022-04-05

Countries

• Netherlands

Study Locations