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

Abstract

Introduction Suicidal thoughts and behaviours are linked to a wide range of mental health conditions. New interest in the psychiatric benefits of nitrous oxide (N2 O) has only recently emerged. The broad pharmacological effects of N2 O are thought to be due in large part to N-methyl-daspartate antagonism and opioid effects. The purpose of this study protocol is to test whether inhalational N2 O exerts rapid antisuicidal effects as a transdiagnostic treatment for suicidal ideation. 

Methods and analysis This is the protocol of a single-centre pilot study of N2 O inhalation in 85 psychiatric inpatients. The initial 45-min double-blind, randomised, placebo-controlled inhalation session either consists of 50% N2 O and 50% oxygen (‘active treatment’) or 50% oxygen plus air. The primary outcome is the change in Beck Scale for Suicidal Ideation scores between the day before and the day after inhalation. A second inhalation containing N2 O will be administered 1week after the first inhalation to ensure that all study participants receive the active treatment at least once. For the mechanism of action and prediction, a nested biomarker substudy will employ multimodal techniques, including analysis of hair and blood samples and electroencephalography. 

Ethics and dissemination This study was approved by the local ethics committee (‘Kantonale Ethikkommission— Kanton Zürich’) and by the Swiss Agency for Therapeutic Products (Swissmedic). Study results will be disseminated primarily by peer-reviewed scientific journals and also by conference presentations, patient and public events and social media. 

Trial registration number ClinicalTrials.gov ID NCT06636357.

Authors

Kronenberg, G., Bankwitz, A., Provaznikova, B., Müller, M., Quednow, B. B., Seifritz, E., & Olbrich, S.