The efficacy and tolerability of inhaled nitrous oxide in major depressive disorder: a systematic review and meta-analysis.
Psychopharmacology October 1, 2023 Youjia Qiu, Longyuan Li, Aojie Duan et al.
A meta-analysis of four clinical trials involving 133 patients with major depressive disorder found that 50% nitrous oxide produces a rapid and lasting antidepressant effect. Depression severity scores improved significantly at 2 hours, 24 hours, and 2 weeks or more compared with placebo. Response and remission rates were also significantly higher with nitrous oxide. However, patients receiving nitrous oxide had a substantially higher risk of nausea or vomiting. The authors call for further research on lower or titrated concentrations.