Individual Differences in Placebo Analgesic Effects

Person by Situation Interaction: Matching Suggestions to Participants' Motivational Styles

This study examines the effects of placebo suggestions tailored to match or mismatch individual participants' motivational styles-an issue of person-situation 'fit' with important effects in public health settings, but which has been ignored in past research.

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy
• Intervention / Treatment: Behavioral: Placebo cream- "promotion" suggestion; Behavioral: Placebo cream- "prevention" suggestion; Behavioral: Control cream

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tor D Wager, PhD; Phone Number: (603)-646-2196; Email: Tor.D.Wager@Dartmouth.edu

Study Locations

• United States
  • New Hampshire
    • Hanover, New Hampshire, United States, 03755
      • Dartmouth College
      • Contact: Bethany Hunt, BA; Email: bethany.j.hunt@dartmouth.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy participants
• Dominant promotion focus or dominant prevention focus (based on our screening)

Exclusion Criteria:

• Currently or recently suffered from chronic pain (based on screening)
• Cannot tolerate heat pain applied to the forearm, based on a calibration task at the beginning of the experiment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Placebo; All participants will participate in two sessions, one with a placebo suggestion that matches the participant's motivational style, and one with placebo suggestion that does not match their motivational style, in a pseudo-random order.	Behavioral: Placebo cream- "promotion" suggestion; Over-the-counter hand cream will be applied to participants' skin, but they will be told that they are given a highly efficient topical analgesic cream. The suggestion will be based on a "promotion" approach (promoting good feelings).; Behavioral: Placebo cream- "prevention" suggestion; Over-the-counter hand cream will be applied to participants' skin, but they will be told that they are given a highly efficient topical analgesic cream. The suggestion will be based on a "prevention" approach (preventing pain).
Experimental: Control; Each session will also include a control phase, in which the same cream will be applied, and participants will be instructed that the cream has no analgesic effects.	Behavioral: Control cream; In a control condition, with the same cream as in the placebo interventions, participants will be instructed that the cream is a control cream with no effects.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in subjective ratings of acute thermal pain	Following each thermal stimulus, participants are asked to rate how painful it was, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher pain ratings. We will average and compare the pain ratings within participant across interventions.	Measured repeatedly, immediately after thermal stimuli on the day of participation. Averaged and compared across interventions.
Changes in subjective ratings of pain expectations	Before each thermal stimulus, participants are asked to rate how painful they expect the next stimulus to be, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher expectations ratings. We will average and compare the expectation ratings within participant across interventions.	Measured repeatedly, immediately before thermal stimuli on the day of participation. Averaged and compared across interventions.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Facial expressions	We will obtain facial video recordings of participants with a video camera. We will analyze these data according to Facial Action Units (facial expressions) that are known to be related to pain, and compare them across interventions.	Immediate response measured during painful stimulation on the day of participation. Averaged and compared across interventions.
Thermal imaging of the face	We will obtain thermal recordings of participant's face with an infrared camera, and compare the heat signature of the face (the temperature in different parts of the face) across interventions.	Immediate response measured during painful stimulation on the day of participation. Averaged and compared across interventions.
Changes in skin conductance response measured with a Biopac device	Skin conductance will be measured. We will compare the skin conductance response to pain stimuli within participant across interventions.	Immediate response measured during painful stimulation on the day of participation. Averaged and compared across interventions.
Changes in heart rate measured with a Biopac device	Heart rate will be measured. We will compare the heart rate in response to pain stimuli within participant across interventions.	Immediate response measured during painful stimulation on the day of participation. Averaged and compared across interventions.

Collaborators and Investigators

• Sponsor: Trustees of Dartmouth College
• Investigators: Principal Investigator: Tor D Wager, PhD, Dartmouth College

Study record dates

Study Major Dates

• Study Start (Estimated): September 30, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: November 16, 2020
• First Submitted That Met QC Criteria: December 10, 2020
• First Posted (Actual): December 16, 2020

Study Record Updates

• Last Update Posted (Estimated): December 9, 2025
• Last Update Submitted That Met QC Criteria: December 2, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: 230138

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All de-identified data will be publicly shared via public online platforms such as the Open Science Framework (OSF) and Github, and the NIMH Data Archive (NDA), according to the terms and conditions outlined on their website (https://ndar.nih.gov/contribute_data_sharing_regimen.html). Identifying information will not be released, including the facial videos, of which only non-identifiable features will be extracted and shared.
• IPD Sharing Time Frame: All data will be de-identified prior to sharing. Raw data will be submitted to NDA within one year from the end of data collection or 6 months from the acceptance date of the first primary study manuscript on the full dataset (excluding methods development papers), whichever is later. Analyzed data/maps of statistical results and models accompanying each paper will be submitted to NDA/OpenFMRI when the primary study manuscript is accepted.

IPD Sharing Access Criteria

These data would generally be made available to any qualified investigator for neuroimaging studies only including:

i. Research on any brain phenomenon; ii. Neuroimaging research on non-disease traits (intelligence, behavioral traits); iii. Methods development research.

The requesting investigator must provide documentation of local IRB approval.

These data would not be made available to:

i. Any criminal justice organization, because data may not be used for any criminal justice applications; ii. Any commercial entity, because use of the data is limited to not-for-profit organizations and data may not be used for any commercial purposes.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No