Investigating Hope and Expectations in Open-Label Placebos

NCT ID: NCT03517644

Last Updated: 2018-08-23

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 100 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2018-02-10
• Study Completion Date: 2018-08-21

Brief Summary

Research has shown that placebo effects contribute substantially to clinical outcomes. Recent evidence suggests that placebos remain effective even if they are openly described as placebos (so-called Open-Label Placebos). In this study, the investigators examine hope and expectations as components of open-label placebos in an experimental study investigating pain..

Detailed Description

A growing body of research has indicated that placebos contribute substantially to clinical outcomes. Yet, the implementation of deceptive placebos in clinical practice is incompatible with key principles of openness and patient autonomy. However, recent research suggests that placebos remain effective even if they openly described as placebos (so-called Open-Label Placebos (OLP)), hence questioning the necessity of deception in clinical trials. However, research identifying the specific mechanisms underlying OLP is lacking. Therefore, the current study aims to examine hope and expectations as components of OLP in pain.

For this purpose, experimentally induced heat pain is examined. First, all participants receive heat pain stimuli and evaluate them. Next, participants are randomly assigned to one of four groups: (1) a traditional deceptive placebo (DP) group, which is told that they receive an effective analgesic cream, (2) an OLP group inducing hope among the participants that the placebo cream could help them tolerating painful stimuli (OLP hope), (3) and OLP group raising the expectation that the placebo cream will help participants tolerating heat pain (OLP expectation), (4) a control group receiving no cream. Finally, participants receive and evaluate heat pain again.

Conditions

Pain

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Deceptive Placebo (DP)

After pretreatment heat pain assessment, participants are informed that they are about to receive an effective analgesic cream. In fact, they receive a placebo cream. Next, the posttreatment pain assessment is conducted.

Group Type: EXPERIMENTAL

DP

Intervention Type: OTHER

Participants are informed that they are about to receive an effective analgesic cream. They are instructed to apply the cream using a cotton pad.

Placebo cream

Intervention Type: OTHER

The participants receive an inert placebo cream (standard basic cream with oil of thyme produced by a local pharmacy).

Heat pain

Intervention Type: OTHER

Participant receive heat pain stimuli using the suprathreshold method of the Thermo Sensory Analyser (TSA-II), a commonly used device to study pain sensation and analgesic effects.

OLP with Hope (OLP Hope)

After pretreatment heat pain assessment, participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. However, using verbal instructions, the investigator aims to induce hope among the participants that the cream could have a positive effect. Next, the posttreatment pain assessment is conducted.

Group Type: EXPERIMENTAL

OLP Hope

Intervention Type: OTHER

Participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. Therefore, participants are supposed to evaluate the subjective probability for a positive effect of the cream as rather low. However, using verbal instructions, the investigator aims to induce hope among the participants that the cream could have a positive effect for them because this placebo cream did have a positive among some former participants who were similar to the current participant. The emphasis of this similarity (regarding age and sex) aims to induce a feeling of connectedness to previous participants who reported positive effects of the placebo cream.

Placebo cream

Intervention Type: OTHER

The participants receive an inert placebo cream (standard basic cream with oil of thyme produced by a local pharmacy).

Heat pain

Intervention Type: OTHER

Participant receive heat pain stimuli using the suprathreshold method of the Thermo Sensory Analyser (TSA-II), a commonly used device to study pain sensation and analgesic effects.

OLP with Expectations (OLP Expectation)

After pretreatment heat pain assessment, participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. However, using verbal instructions, the investigator aims to raise expectations among the participants that the cream will have a positive effect. Next, the posttreatment pain assessment is conducted.

Group Type: EXPERIMENTAL

OLP Expectation

Intervention Type: OTHER

Participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. However, participants are told that placebos have been shown to contribute substantially to clinical outcomes such as pain intensity/unpleasantness. This positive effect of placebos is reasoned by explaining learning mechanisms such as classical conditioning. We anticipated that after hearing this instruction, participants would consider it to be likely that the placebo has a positive effect for them.

Placebo cream

Intervention Type: OTHER

The participants receive an inert placebo cream (standard basic cream with oil of thyme produced by a local pharmacy).

Heat pain

Intervention Type: OTHER

Participant receive heat pain stimuli using the suprathreshold method of the Thermo Sensory Analyser (TSA-II), a commonly used device to study pain sensation and analgesic effects.

Control

After pretreatment heat pain assessment, this group does not receive an intervention targeting pain sensation prior to the posttreatment pain assessment.

Group Type: EXPERIMENTAL

Heat pain

Intervention Type: OTHER

Participant receive heat pain stimuli using the suprathreshold method of the Thermo Sensory Analyser (TSA-II), a commonly used device to study pain sensation and analgesic effects.

Interventions

DP

Participants are informed that they are about to receive an effective analgesic cream. They are instructed to apply the cream using a cotton pad.

Intervention Type: OTHER

OLP Hope

Participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. Therefore, participants are supposed to evaluate the subjective probability for a positive effect of the cream as rather low. However, using verbal instructions, the investigator aims to induce hope among the participants that the cream could have a positive effect for them because this placebo cream did have a positive among some former participants who were similar to the current participant. The emphasis of this similarity (regarding age and sex) aims to induce a feeling of connectedness to previous participants who reported positive effects of the placebo cream.

Intervention Type: OTHER

OLP Expectation

Participants are informed that they are about to receive an placebo cream. They are told that the cream has no active pharmacological ingredient. However, participants are told that placebos have been shown to contribute substantially to clinical outcomes such as pain intensity/unpleasantness. This positive effect of placebos is reasoned by explaining learning mechanisms such as classical conditioning. We anticipated that after hearing this instruction, participants would consider it to be likely that the placebo has a positive effect for them.

Intervention Type: OTHER

Placebo cream

The participants receive an inert placebo cream (standard basic cream with oil of thyme produced by a local pharmacy).

Intervention Type: OTHER

Heat pain

Participant receive heat pain stimuli using the suprathreshold method of the Thermo Sensory Analyser (TSA-II), a commonly used device to study pain sensation and analgesic effects.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• sufficient German language knowledge
• at least 18 years old

Exclusion Criteria

• current mental disorder
• current medical disease
• studying psychology or medicine
• pregnancy or breastfeeding period
• intake of drugs
• severely visually impaired

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Philipps University Marburg

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Tobias Kube, M. Sc.

Role: PRINCIPAL_INVESTIGATOR

Philipps University Marburg

Locations

Philipps-University of Marburg

Marburg, Hesse, Germany

Countries

Germany

Other Identifiers

2017-58v

Identifier Type: -

Identifier Source: org_study_id