Brain and Genetic Predictors of Individual Differences in Pain and Analgesia (PAINGEN)

The purpose of the study is to gain a better understanding of pain processing in the brain. Our understanding of how pain is processed in the brain is limited. We are testing for individual differences in pain perception and emotion.

Study Overview

• Status: Completed
• Conditions: Pain, Acute
• Intervention / Treatment: Behavioral: Placebo Cream; Behavioral: Control Cream

• Study Type: Observational
• Enrollment (Actual): 541

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Boulder, Colorado, United States, 80309
      • University of Colorado, Boulder

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

The CTS includes 727 same-sex twin pairs between 26-38 years old (as of Spring 2017), originally derived from the Colorado Twin Registry, a population based registry, housed at the Institute for Behavioral Genetics (IBG) at the University of Colorado since 1984, with three previous waves of data collection (1997-2002, 2002-2008, and 2009-2014).

Description

Inclusion Criteria:

• Participants must be registered in the Colorado Community Twin Sample (CTS).

Exclusion Criteria:

• Not being registered in the Colorado Community Twin Sample (CTS).
• Any MRI contraindications.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Single group; All participants are administered Control and Placebo creams (two interventions), with thermal and mechanical painful stimuli delivered repeatedly after each intervention. The order of intervention testing is Control, Placebo, Placebo, Control in a fixed order. All interventions are completed within a single testing session.

Behavioral: Placebo Cream; In the Placebo intervention, participants are given an inert cream with instructions that it is "Prodicaine, an effective pain-relieving drug". The cream is applied to two fingers on the left hand.; Behavioral: Control Cream; In the Control intervention, participants are given an inert cream with instructions that it is "a control cream with no effects" . The cream is applied to two fingers on the left hand.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Rating Scores Made on a Visual Analog Scale (VAS)	Self reported pain using a Visual Analogue Scale (VAS) ranging from 0-100 (with 0 representing "no pain at all" and 100 representing "most intense pain imaginable (in the context of the experiment)). Higher scores indicate more pain. 0 is the minimum value and 100 is the maximum value. This scale is used for both thermal and mechanical pain. Reported values reflect averages of VAS ratings for individual stimuli for each of thermal and mechanical pain.	Measured during pain tasks at a single 4 hour experimental session (within one month of screening completion).

Collaborators and Investigators

• Sponsor: Trustees of Dartmouth College
• Collaborators: QIMR Berghofer Medical Research Institute
• Investigators: Principal Investigator: Tor Wager, PHD, University of Colorado, Boulder

Study record dates

Study Major Dates

• Study Start (Actual): November 7, 2018
• Primary Completion (Actual): October 1, 2023
• Study Completion (Actual): October 1, 2023

Study Registration Dates

• First Submitted: December 14, 2018
• First Submitted That Met QC Criteria: December 17, 2018
• First Posted (Actual): December 20, 2018

Study Record Updates

• Last Update Posted (Actual): June 4, 2025
• Last Update Submitted That Met QC Criteria: May 22, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Acute Pain
• Other Study ID Numbers: Pain Genetics

Drug and device information, study documents

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