The giggling cure

I am surprised to read this:

A new study at the University of Chicago Medicine and Washington University found that a single inhalation session with 25% nitrous oxide gas was nearly as effective as 50% nitrous oxide at rapidly relieving symptoms of treatment-resistant depression, with fewer adverse side effects. The study, published June 9 in Science Translational Medicine, also found that the effects lasted much longer than previously suspected, with some participants experiencing improvements for upwards of two weeks.  ...

Often called "laughing gas," nitrous oxide is frequently used as an anesthetic that provides short-term pain relief in dentistry and surgery.

In a prior study, the investigators tested the effects of a one-hour inhalation session with 50% nitrous oxide gas in 20 patients, finding that it led to rapid improvements in patient's depressive symptoms that lasted for at least 24 hours when compared to placebo. However, several patients experienced negative side effects, including nausea, vomiting and headaches....

In the new study, the investigators repeated a similar protocol with 20 patients, this time adding an additional inhalation session with 25% nitrous oxide. They found that even with only half the concentration of nitrous oxide, the treatment was nearly as effective as 50% nitrous oxide, but this time with just one quarter of the negative side effects.

Furthermore, the investigators looked at patients' clinical depression scores after treatment over a longer time course; while the last study only evaluated depression symptoms up to 24 hours after treatment, this new study conducted additional evaluations over two weeks. To their surprise, after just a single administration, some patients' improvements in their depression symptoms lasted for the entire evaluation period. 

Many years ago, a friendly dentist offered to give me nitrous oxide when I didn't really need it, just to see what it was like.   I did, indeed, giggle a lot at anything said.