Nitrous oxide, or laughing gas, has got some pretty bad press in the last year for being a potentially dangerous legal high.
But a new study has suggested the drug could be used as an effective treatment for severe depression.
Researchers at the Washington University School of Medicine found that symptoms of clinical depression improved in two thirds of patients when they received nitrous oxide.
In comparison, only a third of participants reported reduced symptoms when given a placebo.
Although a relatively small study of just 20 participants, the results suggest further research into the effects of nitrous oxide may be worthwhile.
Antidepressants currently prescribed are thought to only be effective in around one third of cases, and partially effective in another third.
The last third of cases get no benefit at all, meaning talking therapy is usually the only other treatment available for a person with depression.
The majority of patients in the study reported an improvement in their symptoms only two hours after treatment with nitrous oxide. Traditional antidepressants can take a number of weeks to work.
“If our findings can be replicated, a fast-acting drug like this might be particularly useful in patients with severe depression who may be at risk for suicide and who need help right away,” said Charles F. Zorumski, Professor and head of the Department of Psychiatry and director of the Taylor Family Institute.
“Or perhaps the drug could be used to relieve symptoms temporarily until more conventional treatments begin to work.”
Further study is needed on the side effects of nitrous oxide before it can be prescribed as a treatment for depression.
Drug advisory website Talk To Frank states: "Nitrous oxide can cause dizziness or affect your judgement, which might make you act carelessly or dangerously and put you at risk of hurting yourself, particularly in an unsafe environment.
"Heavy regular use of nitrous oxide can lead to deficiency of vitamin B12 and to a form of anaemia.
"The severe B12 deficiency can lead to serious nerve damage in some cases, which causes tingling and numbness n the fingers and toes and other extremities, and even difficulties with walking and pains in affected areas."
The Washington University study is published in the journal Biological Psychiatry.