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 July 16, 2025 Golo Kronenberg, Anna Bankwitz, Barbora Provaznikova et al.
Nitrous oxide (N2O) may offer rapid antisuicidal effects across mental health conditions, with its pharmacological action thought to involve NMDA antagonism and opioid effects. This protocol describes a single-centre pilot study of 85 psychiatric inpatients. In a double-blind, randomized, placebo-controlled design, the first 45-minute inhalation session delivers either 50% N2O with 50% oxygen or 50% oxygen plus air. Suicidal ideation is measured by the Beck Scale for Suicidal Ideation before and after inhalation. A second N2O inhalation one week later ensures all participants receive active treatment. A nested biomarker substudy using hair, blood, and EEG will explore mechanisms and prediction.