Characterization of CB1 Receptors Using [11-C]OMAR in Opioid Use Disorder

August 28, 2026 updated by: Anahita Bassir Nia, Yale University
The goals of this sub-study is to assess CB1R availability in early abstinent individuals with OUD (following opioid agonist therapy - OAT stabilization) and in matched healthy controls.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Investigators will use PET imaging to investigate CB1R availability in treatment-seeking individuals with OUD during the early phase of OAT, compared to healthy controls (HCs). Using PET imaging with the CB1R-specific radioligand [¹¹C]OMAR, investigators will assess CB1R availability in predefined brain regions. Investigators will characterize group differences in CB1R availability, evaluate the relationship between CB1R alterations and negative emotional states, including mood, anxiety, and perceived stress, as well as risk of opioid relapse (defined as time to first use of non-prescribed opioids) over a 90-day follow-up period.

Study Type

Interventional

Enrollment (Estimated)

110

Phase

  • 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 Backup

Study Locations

  • United States
    • Connecticut
      • New Haven, Connecticut, United States, 06519
        • Connecticut Mental Health Center, Clinical Neuroscience Research Unit
        • Principal Investigator:
          • Anahita Bassir Nia, MD
        • Contact:

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

All

  • Normal screening bloodwork.
  • Adequate arterial access for placement of an arterial line and blood sampling per study protocol.

OUD Participants:

  • Diagnosis of opioid use disorder (OUD) according to DSM-5 criteria.
  • Actively seeking treatment for OUD.
  • Willingness to initiate opioid agonist therapy (OAT) with buprenorphine.

Healthy Controls:

  • Good general physical health.
  • No current or past diagnosis of any psychiatric or substance use disorders.

Exclusion Criteria:

All

  • Any current major medical condition that, in the opinion of the Principal Investigator, poses a risk for PET procedures.
  • Prior participation in research studies within the past year that would result in cumulative radiation exposure exceeding annual limits.
  • Presence of ferromagnetic metal in the body, pacemaker, or other contraindications to MRI.
  • Positive pregnancy test or current lactation.
  • History of neurological conditions, including stroke or seizure disorders.

OUD Participants

  • Current or past diagnosis of a serious psychiatric disorder.
  • Current diagnosis of any substance use disorder other than nicotine or opioids.
  • Use of any substances within the past 30 days.
  • Current use of SSRIs or benzodiazepines or use within the past 30 days.
  • Previous enrollment in the main study.

Healthy Controls:

  • Current or past diagnosis of any psychiatric disorder.
  • Current diagnosis of any substance use disorder (excluding nicotine).
  • Use of any substances within the past 30 days.

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: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Healthy Volunteers
Healthy volunteers with no current or past major medical or psychiatric history
Drug: [11C]OMAR
For each [11C]OMAR PET scan, up to 20 mCi of [11C]OMAR will be administered.
Other Names:
  • [11C] JHU75528
Other: Opioid Use Disorder in Opioid Agonist Therapy (OAT)
Patients diagnosed with opioid use disorder during the early phase of opioid agonist therapy
Drug: [11C]OMAR
For each [11C]OMAR PET scan, up to 20 mCi of [11C]OMAR will be administered.
Other Names:
  • [11C] JHU75528

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
CB1R Availability
Time Frame: Day 7
To compare cortical CB1R availability (volume of distribution, mL/cm3) assessed using brain PET imaging in individuals diagnosed with opioid use disorder on chronic methadone maintenance vs. matched healthy controls.
Day 7
Mean Beck Depression Inventory (BDI) score
Time Frame: Days 7, 28, 49, 70, 90
A 21-question self-report tool to assess depression symptoms. Total score range 0 to 63, higher scores indicating more severe symptoms.
Days 7, 28, 49, 70, 90
Mean Anxiety Inventory (BAI) score
Time Frame: Days 7, 28, 49, 70, 90
A 21-question self-report tool to assess anxiety symptoms. Total score range 0 to 63, higher scores indicating more severe anxiety.
Days 7, 28, 49, 70, 90
Mean Perceived Stress Scale (PSS) score
Time Frame: Days 7, 28, 49, 70, 90
The PSS is a 10-item self- report scale. PSS scores are obtained by reversing responses to the four positively stated items (items 4, 5, 7, & 8) and then summing across all scale items. Total score range from 0-40 with higher scores indicate greater levels of stress.
Days 7, 28, 49, 70, 90
Mean Opioid Relapse days
Time Frame: Days 7, 14, 21, 28, 35, 42, 49, 56, 70, 77, 84, 90
Mean Opioid Relapse days assessed using Timeline Follow Back (TLFB)
Days 7, 14, 21, 28, 35, 42, 49, 56, 70, 77, 84, 90

Collaborators and Investigators

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

Sponsor

Yale University

Collaborators

National Institute on Drug Abuse (NIDA)

Investigators

  • Principal Investigator: Anahita Bassir Nia, MD, Yale 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 (Estimated)

September 1, 2026

Primary Completion (Estimated)

August 1, 2030

Study Completion (Estimated)

August 1, 2030

Study Registration Dates

First Submitted

August 28, 2026

First Submitted That Met QC Criteria

August 28, 2026

First Posted (Actual)

September 2, 2026

Study Record Updates

Last Update Posted (Actual)

September 2, 2026

Last Update Submitted That Met QC Criteria

August 28, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2000033525_a
  • 1R01DA063712-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

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.

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