A review by researchers from the University of Birmingham and the University of Oxford in the UK has found that controlled doses of laughing gas (or nitrous oxide) really can provide quick-acting relief from depression.

The treatment seems to be viable over longer periods of time, with repeated doses, and can be effective in individuals with both major depressive disorder (MDD) and treatment-resistant depression (TRD) – some of the people who are hardest to treat.

"This population has often lost hope of recovery, making the results of this study particularly exciting," says consultant psychiatrist Steven Marwaha, from the University of Birmingham.

"These findings highlight the urgent need for new treatments that can complement existing care pathways, and further evidence is needed to understand how this approach can best support people living with severe depression."