SuicidalityPhase 2NITOSNCT06636357
Nitrous Oxide in the Treatment of Acute Suicidal Ideation
A Phase 2 study testing 50% N2O plus 50% O2 and Oxygen (O2) in people with Suicidality and EEG, run by University of Zurich at 1 site in Switzerland.
Trial summary
The primary aim of the NITOS study is to investigate the potential rapid antisuicidal effects of N2O in the transdiagnostic treatment of suicidal ideation. On day 1, patients will receive either nitrous oxide (50% N2O balanced with oxygen) or placebo (50% oxygen balanced with air). Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Suicidality, EEG, Suicidal Ideation
- What is being tested?
- 50% N2O plus 50% O2 and Oxygen (O2)
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 85 participants
- Where
- 1 siteSwitzerland
- Study dates
- 13 Jan 2025to 30 Sep 2026
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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
- Ability to give written informed consent
- Moderate to severe suicidal ideation defined as a score ≥3 on the Montgomery-Asberg Depression Rating Scale (MADRS; Schmidtke et al., 1985) suicide item (item #10) as well as a self-report Beck Scale for Suicide Ideation (BSS; Kliem et al., 2017) items #4 plus #5 score ≥ 2
- Plasma homocysteine level ≤ 14 µmol/l
Who cannot join
- Organic, including symptomatic, mental disorders (F00-F09; lifetime diagnosis)
- Schizophrenia, schizotypal and delusional disorders (F20-F29; lifetime diagnosis)
- Mental and behavioral disorders due to psychoactive substance use. Nicotine and cannabis will be ignored (F10-F19)
- Non-medical (i.e., recreational) use of inhalational N2O during the last 12 months
- Past intolerance or hypersensitivity to N2O
- Critical illness
Show all 16Show fewer
- Severe cardiac disease
- Pregnancy or breastfeeding
- Pulmonary hypertension
- Chronic cobalamin or folate deficiency unless treated with folic acid and/or vitamin B12
- History or evidence of any other medical or neurological condition that would expose the subject to an undue risk of a significant adverse event as determined by the clinical judgment of the investigator
- Treatment with ketamine/esketamine during the last 4 weeks
- Treatment with opioid medications during the last 3 months
- Treatment with vagus nerve stimulation (VNS) or electroconvulsive therapy (ECT) within the last 3 months
- Recent (within the last 4 weeks) or current use of benzodiazepines in excess of 5 mg lorazepam or equivalent per day
- Finally, any other factors that, in the investigator's judgment, would unduly impact patient safety or compliance during the study.
Trial locations and contacts
1 site in 1 country.
Switzerland1 site, 1 recruiting
- Recruiting
Psychiatric University Hospital Zurich
Zurich, 8032
Angelina Frasch, 0041583843666, angelina.frasch@pukzh.ch
About this study
The primary aim of the NITOS study is to investigate the potential rapid antisuicidal effects of N2O in the transdiagnostic treatment of suicidal ideation. On day 1, patients will receive either nitrous oxide (50% N2O balanced with oxygen) or placebo (50% oxygen balanced with air). Seven days after the first inhalation, a second inhalation will be performed. All patients will receive N2O at least once during this trial. While the first inhalation will be double-blind, only the patients but not the raters will be blinded to the second inhalation (day 8). For mechanism of action and prediction, a nested biomarker substudy will employ multimodal techniques including analysis of hair and blood samples, and EEG.
- Conditions
- Suicidality, EEG, Suicidal Ideation, Nitrous Oxide, Biomarkers / Blood, Biomarkers / Hair
- Being tested
- 50% N2O plus 50% O2, Oxygen (O2)
- Keywords
- suicidality, nitrous oxide, suicidal ideation, depression
- Medical subject headings
- Suicidal Ideation, Depression
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
50% N2O plus 50% O2Drug
Inhalation of 50% N2O plus 50% O2 for 45 min
Oxygen (O2)Drug
50% O2 plus 50% air for 45 min
| Study group | Role | What they receive |
|---|---|---|
| 50% nitrous oxide (N2O) plus 50% oxygen | Experimental | Patients will be treated with N20 (50% N2O combined with 50% oxygen) for 45 minutes. Both the study subject and the rater will be blinded to the treatment assignment. Receives: Drug: 50% N2O plus 50% O2 |
| 50% oxygen plus 50% air | Placebo comparator | Here, patients will be treated with 50% oxygen plus air for 45 minutes. Both the study subject and the rater will be blinded to the treatment assignment. Receives: Drug: Oxygen (O2) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Beck Scale for Suicidal Ideation (BSS)
Change of BSS score between Day 0 and Day 2. Double-blind treatment with either N2O or placebo inhalation on Day 1.
Measured: Day 0 to Day 2
Secondary outcomes (4)
Montgomery-Åsberg Depression Rating Scale (MADRS )
Measured: Day 0 to Day 2
EEG changes associated with N2O / placebo inhalation
EEG will be performed before, during, and after inhalation
Measured: Day 1
Suicide Visual Analog Scale (S-VAS)
Briefly, the S-VAS uses the phrase "urge to kill myself". Next to the phrase, the patient sees a line that is anchored on the left with the word "none" and on the right with the word "extreme" . Score ranges from 0 to 100.
Measured: Day 1
Perceived Burdensomeness Visual Analog Scale (PB-VAS)
The PB-VAS uses the phrase "like a burden". Next to the phrase, the patient sees a line that is anchored on the left with the word "none" and on the right with the word "extreme" . Score ranges from 0 to 100.
Measured: Day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Oct 2024
- Study start13 Jan 2025
- Primary completion30 Sep 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for SuicidalityStudies of the same condition, open and under way.
- More trials run by University of ZurichThe 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
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 85 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Zurich
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sebastian Olbrich, University of Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06636357
- Sponsor's protocol ID
- 2024-01005
- Acronym
- NITOS
- Status last verified
- Oct 2024
- First submitted
- 6 Sep 2024
- Last updated
- 16 Jan 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Kronenberg G, Bankwitz A, Provaznikova B, Muller M, Quednow BB, Seifritz E, Olbrich S. Inhalational nitrous oxide as a transdiagnostic approach for the treatment of suicidal ideation and suicidality in psychiatric inpatients: protocol for a double-blind randomised, controlled clinical single-centre trial. BMJ Open. 2025 Jul 16;15(7):e096825. doi: 10.1136/bmjopen-2024-096825.
PubMed 40669910
Study at a glance
From the registry record, last updated by the sponsor on 16 Jan 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Nitrous Oxide in the Treatment of Acute Suicidal Ideation
- ClinicalTrials.gov ID
- NCT06636357
- Acronym / sponsor ID
- NITOS / 2024-01005
- Conditions
- Suicidality, EEG, Suicidal Ideation, Nitrous Oxide, Biomarkers / Blood, Biomarkers / Hair
- Keywords
- suicidality, nitrous oxide, suicidal ideation, depression
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 85 participants (estimated)
- Lead sponsor
- University of ZurichUniversity, hospital or other
- Study start
- 13 Jan 2025 (actual)
- Primary completion
- 30 Sep 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 10 Oct 2024 (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.
The primary aim of the NITOS study is to investigate the potential rapid antisuicidal effects of N2O in the transdiagnostic treatment of suicidal ideation. On day 1, patients will receive either nitrous oxide (50% N2O balanced with oxygen) or placebo (50% oxygen balanced with air). Seven days after the first inhalation, a second inhalation will be performed. All patients will receive N2O at least once during this trial. While the first inhalation will be double-blind, only the patients but not the raters will be blinded to the second inhalation (day 8). For mechanism of action and prediction, a nested biomarker substudy will employ multimodal techniques including analysis of hair and blood samples, and EEG.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 50% nitrous oxide (N2O) plus 50% oxygen | Experimental | Drug: 50% N2O plus 50% O2Patients will be treated with N20 (50% N2O combined with 50% oxygen) for 45 minutes. Both the study subject and the rater will be blinded to the treatment assignment. |
| 50% oxygen plus 50% air | Placebo comparator | Drug: Oxygen (O2)Here, patients will be treated with 50% oxygen plus air for 45 minutes. Both the study subject and the rater will be blinded to the treatment assignment. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Ability to give written informed consent
- Moderate to severe suicidal ideation defined as a score ≥3 on the Montgomery-Asberg Depression Rating Scale (MADRS; Schmidtke et al., 1985) suicide item (item #10) as well as a self-report Beck Scale for Suicide Ideation (BSS; Kliem et al., 2017) items #4 plus #5 score ≥ 2
- Plasma homocysteine level ≤ 14 µmol/l
Key exclusion criteria (16 listed)
- Organic, including symptomatic, mental disorders (F00-F09; lifetime diagnosis)
- Schizophrenia, schizotypal and delusional disorders (F20-F29; lifetime diagnosis)
- Mental and behavioral disorders due to psychoactive substance use. Nicotine and cannabis will be ignored (F10-F19)
- Non-medical (i.e., recreational) use of inhalational N2O during the last 12 months
- Past intolerance or hypersensitivity to N2O
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 |
|---|---|---|
| 50% N2O plus 50% O2Inhalation of 50% N2O plus 50% O2 for 45 min | Drug | 50% nitrous oxide (N2O) plus 50% oxygen |
| Oxygen (O2)50% O2 plus 50% air for 45 min | Drug | 50% oxygen plus 50% air |
Primary outcome
Beck Scale for Suicidal Ideation (BSS)
Time frame: Day 0 to Day 2
Change of BSS score between Day 0 and Day 2. Double-blind treatment with either N2O or placebo inhalation on Day 1.
4 secondary outcomes
Montgomery-Åsberg Depression Rating Scale (MADRS )
Time frame: Day 0 to Day 2
EEG changes associated with N2O / placebo inhalation
Time frame: Day 1
Suicide Visual Analog Scale (S-VAS)
Time frame: Day 1
Perceived Burdensomeness Visual Analog Scale (PB-VAS)
Time frame: Day 1
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Jan 2025.
- Derived from this study: PubMed 40669910Kronenberg G, Bankwitz A, Provaznikova B, Muller M, Quednow BB, Seifritz E, Olbrich S. Inhalational nitrous oxide as a transdiagnostic approach for the treatment of suicidal ideation and suicidality in psychiatric inpatients: protocol for a double-blind randomised, controlled clinical single-centre trial. BMJ Open. 2025 Jul 16;15(7):e096825. doi: 10.1136/bmjopen-2024-096825.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
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 50% N2O plus 50% O2 and Oxygen (O2) in people with Suicidality and EEG, run by University of Zurich at 1 site in Switzerland.
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 3 inclusion and 16 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: status not confirmed, as of the sponsor's last update on 16 Jan 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 Switzerland. 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?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Angelina Frasch (0041583843666, angelina.frasch@pukzh.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Beck Scale for Suicidal Ideation (BSS) (time frame: Day 0 to Day 2). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06636357, which also lists 1 linked publication.
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 16 Jan 2025.