NCT03736538

Nitrous Oxide- Suicidal Ideation

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

• Status: Enrolling By Invitation
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 50 (estimated)
• Sponsor: Washington University School of Medicine · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Not accepted

Summary

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.

Conditions

• Major Depressive Disorder
• Depression
• Mood Disorders
• Suicidal Ideation

Interventions

Type	Name	Description
DRUG	Nitrous Oxide	Nitrous oxide, an odorless, colorless gas typically used as an induction agent for general anesthesia or for dental sedation, is a known N-methyl-D-aspartate (NMDA) antagonist. It will be given at 50% nitrous oxide/50% oxygen in this study.
DRUG	Placebo gas	Placebo gas given at 50% nitrogen \[inert\]/50% oxygen.

Timeline

• Start date: 2018-10-30
• Primary completion: 2026-09-01
• Completion: 2026-12-01
• First posted: 2018-11-09
• Last updated: 2025-12-22

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study