Understanding How Opioids Affect the Experiential and Neural Signatures of Social Experiences

September 9, 2026 updated by: San Diego State University
The study is a randomized, placebo-controlled design with the opioid antagonist, oral naltrexone. Following random assignment, participants will take 50mg of naltrexone or placebo once a day for 7 days. On days 1 - 7, participants complete reports of their feelings of social connection and mood in order to assess more naturalistic feelings in response to opportunities for social connection outside of the laboratory setting. Additionally, at the end of each day, they complete a physical symptoms questionnaire. On the 7th day, participants will come to the SDSU MRI scanning facility to complete tasks designed to elicit feelings of social connection in the fMRI scanner. After the scan, feelings in response to the scanner tasks will be collected.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
217

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • California
      • San Diego, California, United States, 92120
        • San Diego State University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 25 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • good health
  • English fluency
  • willing to provide contact information for 4-6 close others
  • willing to provide digital photographs of 2 close others
  • own a smartphone

Exclusion Criteria:

  • presence of medical devices, implants, or other metal objects in or on the body that cannot be removed
  • tattooed eyeliner
  • a body habitus prohibiting MRI scanning
  • claustrophobia
  • self-reported chronic mental or physical illness
  • current and regular use of prescription medication
  • previous history of having difficulty taking pills
  • current use of opioid analgesics
  • depressive symptoms above a 9 on Patient Health Questionnaire
  • excessive alcohol use
  • positive urine drug test
  • body mass index (BMI) greater than 35
  • pregnancy or plans to become pregnant in next 6 months
  • positive urine pregnancy test

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Naltrexone
50mg naltrexone HCL once daily for seven days by mouth
Drug: Naltrexone Hydrochloride
oral naltrexone
Other Names:
  • oral naltrexone
  • naltrexone pill
  • naltrexone
  • naltrexone oral tablet
Placebo Comparator: placebo
sugar pill once daily for seven days by mouth
Drug: Placebo
oral sugar pill
Other Names:
  • sugar pill

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Daily feelings of social connection via ecological momentary assessment
Time Frame: post-treatment, change across 7 days
State feelings of social connection outside of the lab
post-treatment, change across 7 days
Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs
Time Frame: Day 7, approximately 60 mins after taking study drug
In the MRI scanner, participants read sentences written by people they know and people they do not know in a block design. In a second task they view images of people they know, those they do not know, and other emotional images. Brain activity will be measured as BOLD activity in response to stimuli from known (vs. unknown) people using functional magnetic resonance imaging (FMRI). Based on a priori hypotheses, brain activity will be masked to activity in structural regions-of- interest (ROIs) of the ventral striatum (VS), middle-insula (MI), anterior cingulate cortex (ACC) and ventromedial prefrontal cortex (VMPFC).
Day 7, approximately 60 mins after taking study drug
feelings in response to neuroimaging tasks
Time Frame: Day 7, approximately 150 minutes after taking study drug
Feelings of social connection and general positive affect in response to the neuroimaging tasks will be reported on a scale of 1 (not at all) to 7 (very)
Day 7, approximately 150 minutes after taking study drug

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
physical symptoms via daily diary
Time Frame: end of day on days 1-7
Physical symptoms previously associated with naltrexone will be assessed as well as the subjective experience of the symptoms.
end of day on days 1-7

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
San Diego State University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute on Drug Abuse (NIDA)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Tristen Inagaki, PhD, San Diego State University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 16, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 18, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 18, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 15, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 13, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 16, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 9, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HS-2020-0188-SMT
  • R01DA052883 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data and resources from the current study will be deposited in the Open Science Framework (OSF) and OpenNEURO.org, in accordance with the NIH Data Sharing Policy. In addition, results will be posted on the ClinicalTrials.gov website within 1 year of the study's completion date.

IPD Sharing Time Frame

After publication of the primary findings.

IPD Sharing Access Criteria

Researchers in both private and public sector

IPD Sharing Supporting Information Type

  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings