NaltrexoneEarly Phase 1NCT05007561
Understanding How Opioids Affect the Experiential and Neural Signatures of Social Experiences
A Early Phase 1 study testing Naltrexone Hydrochloride in people with Naltrexone and Placebo, run by San Diego State University at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 25 yearsHealthy volunteers can take part
- Conditions the study is for
- Naltrexone, Placebo
- What is being tested?
- Naltrexone Hydrochloride
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 217 participants
- Where
- 1 siteUnited States
- Study dates
- 16 Nov 2021to 18 Mar 2026
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 25 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Show all 14Show fewer
- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
San Diego State University
San Diego, California, 92120
About this study
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.
- Conditions
- Naltrexone, Placebo
- Being tested
- Naltrexone Hydrochloride, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Naltrexone HydrochlorideDrug
Also called oral naltrexone, naltrexone pill, naltrexone, naltrexone oral tablet
oral naltrexone
PlaceboDrug
Also called sugar pill
oral sugar pill
| Study group | Role | What they receive |
|---|---|---|
| Naltrexone | Experimental | 50mg naltrexone HCL once daily for seven days by mouth Receives: Drug: Naltrexone Hydrochloride |
| placebo | Placebo comparator | sugar pill once daily for seven days by mouth Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Daily feelings of social connection via ecological momentary assessment
State feelings of social connection outside of the lab
Measured: post-treatment, change across 7 days
Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs
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).
Measured: Day 7, approximately 60 mins after taking study drug
feelings in response to neuroimaging tasks
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)
Measured: Day 7, approximately 150 minutes after taking study drug
Secondary outcomes (1)
physical symptoms via daily diary
Physical symptoms previously associated with naltrexone will be assessed as well as the subjective experience of the symptoms.
Measured: end of day on days 1-7
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Aug 2021
- Study start16 Nov 2021
- Primary completion18 Mar 2026
- Study completion18 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for NaltrexoneStudies of the same condition, open and under way.
- More trials run by San Diego State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 217 participants (actual)
Sponsor and investigators
- Lead sponsor
- San Diego State University
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Responsible party
- Sponsor
- Investigators
- Tristen Inagaki, PhD, Principal investigator, San Diego State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05007561
- Sponsor's protocol ID
- HS-2020-0188-SMT
- Other IDs
- R01DA052883
- Status last verified
- Sep 2026
- First submitted
- 15 Jul 2021
- Last updated
- 10 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Study at a glance
From the registry record, last updated by the sponsor on 10 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Understanding How Opioids Affect the Experiential and Neural Signatures of Social Experiences
- ClinicalTrials.gov ID
- NCT05007561
- Acronym / sponsor ID
- HS-2020-0188-SMT
- Conditions
- Naltrexone, Placebo
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 217 participants (actual)
- Lead sponsor
- San Diego State UniversityUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- 16 Nov 2021 (actual)
- Primary completion
- 18 Mar 2026 (actual)
- Study completion
- 18 Mar 2026 (actual)
- First posted
- 16 Aug 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Naltrexone | Experimental | Drug: Naltrexone Hydrochloride50mg naltrexone HCL once daily for seven days by mouth |
| placebo | Placebo comparator | Drug: Placebosugar pill once daily for seven days by mouth |
Who may qualify
- Ages
- 18 to 25 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (14 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Naltrexone HydrochlorideAlso: oral naltrexone, naltrexone pill, naltrexone, naltrexone oral tabletoral naltrexone | Drug | Naltrexone |
| PlaceboAlso: sugar pilloral sugar pill | Drug | placebo |
Primary outcome
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
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).
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)
1 secondary outcome
physical symptoms via daily diary
Time frame: end of day on days 1-7
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Sep 2026.
- Individual participant dataSharing planned: Yes. 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.
Related trials for Naltrexone
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Tristen Inagaki, PhD principal investigator
San Diego State University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Naltrexone Hydrochloride in people with Naltrexone and Placebo, run by San Diego State University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 10 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Daily feelings of social connection via ecological momentary assessment (time frame: post-treatment, change across 7 days). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Sep 2026.