A recent meta-analysis led by the University of Birmingham suggests that nitrous oxide, commonly called laughing gas, could quickly reduce symptoms of major depressive disorder (MDD), including treatment-resistant depression (TRD). Reviewing seven trials and four study protocols, researchers found that a single session with 50% nitrous oxide concentration improved mood within 24 hours, though effects usually lasted less than a week. Repeated sessions offered longer-lasting benefits.
The gas, already used for pain relief in dentistry and childbirth, appears to act on the brain’s glutamate system, similar to ketamine. Kiranpreet Gill, first author, said, “Depression is hard to treat and about half of patients don’t get enough help from regular medication.” Mild side effects like nausea or dizziness were reported, but no serious safety concerns emerged. Further clinical trials are planned in the NHS.