A low dose of nitrous oxide known as laughing gas improves symptoms of severe depression that do not respond to treatment, according to a phase two study published in the journal Science Translational Medicine. The team of researchers from the Universities of Chicago and Washington found that a single one-hour session of inhaling this 25% gas was almost as effective as 50% in improving symptoms of depression for more than two weeks and with fewer side effects.
Nitrous oxide is frequently used as an anesthetic for short-term pain relief in dentistry and surgery. Despite its reputation for laughing gas, patients who were given such a low dose neither high nor high actually fall asleep, explained study lead author Peter Nagele of the University of Chicago.
In a previous study, researchers tested the effects of a one-hour inhalation session with 50% nitrous oxide gas in 20 patients and found that it produced rapid improvements in depressive symptoms lasting at least 24 hours compared to placebo, but several experienced side effects such as nausea, vomiting, and headaches.
Researchers wondered if our previous 50% concentration had been too high and that by lowering it perhaps they could find the right balance that maximizes clinical benefit and minimizes negative side effects.
Twenty-eight patients took part in the study over three months and found that, after a single administration, the improvements in depression symptoms lasted up to two weeks and with a quite dramatic reduction in side effects.