Study Finds Nitrous Oxide May Help Treat Major Depression

BIRMINGHAM, England — December 2, 2025 — Researchers at the University of Birmingham reported that nitrous oxide could be an effective treatment for adults with major depressive disorder who have not responded to traditional antidepressants, according to a study published in the journal eBioMedicine.

The study reviewed clinical data from three trials in which patients inhaled nitrous oxide at a 50% concentration. Results showed a rapid and significant reduction in depressive symptoms within 24 hours of a single treatment. However, these effects did not last beyond one week. Researchers noted that repeated treatments over several weeks appeared to provide longer-lasting relief, indicating that ongoing administration may be necessary for sustained clinical benefits.

Nitrous oxide is believed to act on the brain’s glutamate receptors similarly to ketamine, a fast-acting drug also used to treat depression by temporarily altering brain chemistry. The research team acknowledged variability in how depressive symptoms were measured across the limited number of existing trials, emphasizing the need for further studies and additional clinical trials.

Plans are underway to conduct the first trial within England’s National Health Service to evaluate whether nitrous oxide can be a viable long-term treatment option for major depressive disorder. Officials said the findings could help determine how nitrous oxide might be integrated into NHS care and potentially expand treatment options for patients who have not benefited from standard approaches.

The study also examined potential side effects, finding that adverse effects increased at concentrations above 50%. Researchers stressed the importance of monitoring safety in future clinical applications.

This research adds to ongoing efforts to identify innovative treatments for depression, particularly for individuals who do not respond to existing antidepressant medications.