NCT03736538Enrolling by invitationPhase 1
Nitrous Oxide- Suicidal Ideation
Adjunctive Nitrous Oxide for Acute Suicidal Ideation in Unipolar Depressed Hospitalized Patients
Source: ClinicalTrials.gov · Last updated 22 Dec 2025
Brief summary (registry, in English)
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.
- Status (registry)
- Enrolling by invitation
- Phase (registry)
- Phase 1
- Study type
- Interventional
- Enrollment
- 50 (estimated)
- First submitted
- 6 Nov 2018
- Start date
- 30 Oct 2018
- Primary completion date
- Sept 2026
- Lead sponsor
- Washington University School of Medicine
- Diseases
- Depression
- NCT number
- NCT03736538
What you commit to
- Study type: Interventional · Phase 1
- Planned participants: 50
- From 30 Oct 2018 to the primary completion date, Sept 2026
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- currently receiving electroconvulsive therapy;
- contraindications for nitrous oxide (pneumothorax, bowel obstruction, middle ear occlusion, elevated intracranial pressure, chronic cobalamin and/or folate deficiency treated with folic acid or vitamin B12);
Other illness
- Lifetime DSM-IV (obtained via MINI) diagnoses of schizophrenia, schizoaffective disorders, bipolar disorder, obsessive-compulsive disorder, evidence of severe personality disorder (e.g., history of recurrent self-mutilation/cutting, significant and recurrent tumultuous relationships), and panic disorders;
- significant pulmonary disease and/or requiring supplemental oxygen;
- past 12-month history of head trauma;
Other
- past 12-month substance abuse/dependence other than nicotine;
- active psychotic symptoms;
- administration of other N-Methyl-D-aspartate (NMDA)-receptor antagonist treatment (e.g., ketamine) within two weeks of entry into study;
- women who are pregnant or breastfeeding;
- any other factor that in the investigators' judgment may affect patient safety or compliance.
Who the study is looking for
- Patients aged 18-65 years old;
- current diagnosis of unipolar, major depressive disorder (MDD) without psychosis as defined by the Mini-International Neuropsychiatric Interview (MINI) and The Fourth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) DSM-IV determined by clinical interview and by a baseline score of ≥18 on the HDRS-21 (Hamilton Depression Rating Scale 21-item;
- moderate to severe SI defined as a score ≥3 on the HDRS-21 suicide item (item #3);
- will have good command of the English language;
- will have been voluntarily admitted to the inpatient Psychiatric Units at Barnes-Jewish Hospital/Washington University in St. Louis, MO.
Age in the registry: 18 years to 65 years · Sex: All · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Washington University School of Medicine Coordinator of this site? Confirm its status | St Louis | United States | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.