Depression is no laughing matter.

But a group of Melbourne researchers believe nitrous oxide, commonly known as laughing gas, may hold the key to treating severe depression in people who have not responded to standard therapies.

Carolyn Deng, Professor Paul Myles and Professor Jayashri Kulkarni at The Alfred hospital. Credit:Luis Enrique Ascui

In the first study of its kind in Australia people with depression will inhale about the same amount of nitrous oxide as someone getting a filling at the dentist.

"A patient can effectively come in and sit in a chair and relax and listen to nice music and breathe in the gas and they'll start to feel, perhaps, slightly woozy and a bit better in their mood almost immediately," says Associate Professor Paul Myles, who is leading the study at The Alfred hospital.