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Enrolling by invitation Phase 1 Interventional

Nitrous Oxide- Suicidal Ideation

ClinicalTrials.gov ID: NCT03736538

Public ClinicalTrials.gov record NCT03736538. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 7, 2026, 2:04 AM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

Adjunctive Nitrous Oxide for Acute Suicidal Ideation in Unipolar Depressed Hospitalized Patients

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

Most clinical major depression responds to standard treatments (medication and psychotherapy); however, a significant subset of depressed patients (15-20%) do not respond to these treatments and are referred to as treatment-resistant major depression (TRMD). New treatments for TRMD are needed, and one promising line of research are drugs known as N-methyl-D-aspartate (NMDA) glutamate receptor antagonists. In a recent pilot study, the investigators of this study demonstrated that the NMDA antagonist nitrous oxide is effective in TRMD, reducing depressive symptoms, guilt, and suicidal thinking. To more closely investigate suicidal thinking, this study is designed as a double-blind, randomized, prospective, inpatient trial comparing inhaled nitrous oxide (N2O) plus treatment as usual versus inhaled placebo plus treatment as usual. All unipolar depressed, acutely suicidal inpatients will receive standard treatment for their depression/ suicidal thinking (TAU). Additionally, participants will undergo a maximum of four one hour inhalation sessions as inpatients and 2 booster sessions as outpatients during which they will receive either inhaled nitrous oxide (50% nitrous oxide/50% oxygen = active treatment) or placebo gas (50% nitrogen/50% oxygen). A target total of 50 patients with suicidal ideation and unipolar depression will be enrolled, 25 of whom will be assigned to the TAU control group and 25 of whom will be assigned to the N2O + TAU experimental group.

Study identification

NCT ID
NCT03736538
Recruitment status
Enrolling by invitation
Study type
Interventional
Phase
Phase 1
Enrollment
50 participants

Conditions and interventions

Eligibility (public fields only)

Age range
18 Years to 65 Years
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Oct 29, 2018
Primary completion
Aug 31, 2026
Completion
Nov 30, 2026
Last update posted
Dec 21, 2025

2018 – 2026

United States locations

U.S. sites
1
U.S. states
1
U.S. cities
1
Facility City State ZIP Site status
Washington University School of Medicine St Louis Missouri 63110

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT03736538, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Dec 21, 2025 · Synced Sep 7, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT03736538 live on ClinicalTrials.gov.

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