Obsessive-Compulsive DisorderPhase 2NCT03826693
Efficacy of Nitrous Oxide in OCD: Pilot Study
A Phase 2 study testing Nitrous Oxide and Nitrogen in people with Obsessive-Compulsive Disorder, run by Stanford University at 1 site in United States.
Trial summary
This study investigates whether the commonly used and well-tolerated inhaled anesthetic nitrous oxide can rapidly improve symptoms of OCD. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Obsessive-Compulsive Disorder
- What is being tested?
- Nitrous Oxide and Nitrogen
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 45 participants
- Where
- 1 siteUnited States
- Study dates
- 17 Apr 2021to Oct 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age 18-65
- Primary diagnosis of OCD
- Sufficient severity of OCD symptoms
- Ability to tolerate a treatment-free period
- Capacity to provide informed consent
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Stanford University
Stanford, California, 94304
Pavithra Makunda, MS, 650-723-4095, ocdresearch@stanford.edu
Sindu Menon, MBBS, 650-723-4095, ocdresearch@stanford.edu
About this study
This study investigates whether the commonly used and well-tolerated inhaled anesthetic nitrous oxide can rapidly improve symptoms of OCD.
Read the 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.
- Conditions
- Obsessive-Compulsive Disorder
- Being tested
- Nitrous Oxide, Nitrogen
- Keywords
- OCD, nitrous oxide
- Medical subject headings
- Obsessive-Compulsive Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nitrous OxideDrug
OCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes.
NitrogenDrug
OCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes.
| Study group | Role | What they receive |
|---|---|---|
| Experimental: Nitrous Oxide | Experimental | OCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes. Receives: Drug: Nitrous Oxide |
| Control: Nitrogen | Placebo comparator | OCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes. Receives: Drug: Nitrogen |
What is being measured
The primary outcome is the main question the study is designed to answer.
Improvement in the severity of OCD symptoms as measured by the Yale-Brown Obsessive Compulsive Scale (YBOCS)
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.
Measured: 1 week
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Feb 2019
- Study start17 Apr 2021
- Primary completionSep 2026 (estimated)
- Study completionOct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obsessive-Compulsive DisorderStudies of the same condition, open and under way.
- More trials run by Stanford 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
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- placebo-controlled 2:1 randomized clinical trial.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 45 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- Brain & Behavior Research Foundation
- Responsible party
- Principal investigator, Peter J van Roessel, MD PhD, Stanford University
- Investigators
- Peter J van Roessel, MD, PhD, Principal investigator, Stanford Univeristy
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03826693
- Sponsor's protocol ID
- 48077
- Status last verified
- Aug 2025
- First submitted
- 30 Jan 2019
- Last updated
- 27 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of Nitrous Oxide in OCD: Pilot Study
- ClinicalTrials.gov ID
- NCT03826693
- Acronym / sponsor ID
- 48077
- Conditions
- Obsessive-Compulsive Disorder
- Keywords
- OCD, nitrous oxide
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 45 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- Brain & Behavior Research Foundation
- Study start
- 17 Apr 2021 (actual)
- Primary completion
- Sep 2026 (estimated)
- Study completion
- Oct 2027 (estimated)
- First posted
- 1 Feb 2019 (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.
This study investigates whether the commonly used and well-tolerated inhaled anesthetic nitrous oxide can rapidly improve symptoms of OCD.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- placebo-controlled 2:1 randomized clinical trial.
| Arm | Type | Receives |
|---|---|---|
| Experimental: Nitrous Oxide | Experimental | Drug: Nitrous OxideOCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes. |
| Control: Nitrogen | Placebo comparator | Drug: NitrogenOCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Age 18-65
- Primary diagnosis of OCD
- Sufficient severity of OCD symptoms
- Ability to tolerate a treatment-free period
- Capacity to provide informed consent
Key exclusion criteria (3 listed)
- 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)
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 |
|---|---|---|
| Nitrous OxideOCD participants in this arm will receive 50%oxygen/50% nitrous oxide admixture for 60 minutes. | Drug | Experimental: Nitrous Oxide |
| NitrogenOCD participants in this arm will receive 50%oxygen/50% nitrogen admixture for 60 minutes. | Drug | Control: Nitrogen |
Primary outcome
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.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Aug 2025.
- Stanford Medicine Faculty PageLink provided by the sponsor.
- Rodriguez Lab WebsiteLink provided by the sponsor.
- Individual participant dataSharing planned: No
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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.
Peter J van Roessel, MD, PhD principal investigator
Stanford Univeristy
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Nitrous Oxide and Nitrogen in people with Obsessive-Compulsive Disorder, run by Stanford 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 3 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: looking for participants now, as of the sponsor's last update on 27 Aug 2025. 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?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Pavithra Mukunda, MS (650-723-4095, ocdresearch@stanford.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Improvement in the severity of OCD symptoms as measured by the Yale-Brown Obsessive Compulsive Scale (YBOCS) (time frame: 1 week). 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 27 Aug 2025.