Efficacy of Nitrous Oxide in OCD: Pilot Study

August 20, 2025 updated by: Peter J van Roessel, MD PhD, Stanford University
This study investigates whether the commonly used and well-tolerated inhaled anesthetic nitrous oxide can rapidly improve symptoms of OCD.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Obsessive-compulsive disorder (OCD) is a chronic and disabling disorder characterized by recurrent intrusive thoughts and associated compulsive behaviors that is estimated to affect more than 3 million individuals in the US each year.

This study seeks to explore whether a single inhalation of nitrous oxide gas may bring about rapid symptom relief in OCD.

Study Type

Interventional

Enrollment (Estimated)

45

Phase

  • Phase 2

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
    • California
      • Stanford, California, United States, 94304
        • Recruiting
        • Stanford University
        • Contact:
        • Contact:
        • Principal Investigator:
          • Peter van Roessel, MD, PhD

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

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-65
  • Primary diagnosis of OCD
  • Sufficient severity of OCD symptoms
  • Ability to tolerate a treatment-free period
  • Capacity to provide informed consent

Exclusion Criteria:

  • Psychiatric or medical conditions that make participation unsafe
  • Pregnant or nursing females
  • Concurrent use of any medications that might increase the risk of participation (e.g. drug interactions)

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental: Nitrous Oxide
OCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes.
Drug: Nitrous Oxide
OCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes.
Placebo Comparator: Control: Nitrogen
OCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes.
Drug: Nitrogen
OCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Improvement in the severity of OCD symptoms as measured by the Yale-Brown Obsessive Compulsive Scale (YBOCS)
Time Frame: 1 week
Improvement in OCD severity is measured by the YBOCS (Yale Brown Obsessive-Compulsive Scale), a gold standard measure of obsessions and compulsions. For the YBOCS the minimum units are 0 and Maximum units on the total scale are 40. The higher the number on the YBOCS, the more severe the symptoms. Response is defined as at least a 35% reduction on the YBOCS.
1 week

Collaborators and Investigators

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

Sponsor

Stanford University

Collaborators

Brain & Behavior Research Foundation

Investigators

  • Principal Investigator: Peter J van Roessel, MD, PhD, Stanford Univeristy

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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)

April 17, 2021

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

January 30, 2019

First Submitted That Met QC Criteria

January 30, 2019

First Posted (Actual)

February 1, 2019

Study Record Updates

Last Update Posted (Estimated)

August 27, 2025

Last Update Submitted That Met QC Criteria

August 20, 2025

Last Verified

August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 48077

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

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.

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