doctor makes the patient anesthesia

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ST. LOUIS — For some patients battling depression, standard treatments and therapies simply aren’t enough. Now, a new study finds a mix of oxygen and nitrous oxide — better known as laughing gas — can help these individuals quickly wave goodbye to their mental health troubles.

Researchers from the Washington University School of Medicine in St. Louis say small doses of the colorless gas rapidly improve symptoms of depression in a single session. People who suffer from anxiety and depression, two of the most common mental health issues worldwide, generally take antidepressants to ease their symptoms. However, these medications can take weeks to take effect, with up to a third of cases resulting in no improvement at all.

“A large percentage of patients don’t respond to standard antidepressant therapies — the patients in this study had failed an average of 4.5 antidepressant trials — and it’s very important to find therapies to help these patients,” says study author Professor Charles Conway in a university release. “That we saw rapid improvements in many such patients in the study suggests nitrous oxide may help people with really severe, resistant depression.”

Testing doses of nitrous oxide

Researchers carried out a clinical trial involving 24 patients who received three sessions of laughing gas treatments, one month apart. The patients inhaled NOS for an hour, but with different concentrations of nitrous oxide and oxygen each time.

During the first session, patients breathed in a gas with an even mixture of 50 percent nitrous oxide and 50 percent oxygen. Study authors then reduced the amount of nitrous oxide to just 25 percent. Finally, the team gave patients a placebo gas in the third session, containing 100 percent oxygen.

“You can’t really get a better comparison group than when you compare a person to himself or herself,” co-author Professor Peter Nagele explains. “Serving as your own control is ideal. The alternative is studying the effects of a drug in two similar groups of people in which you either get one treatment or another. But the problem with that is that you need much larger numbers of patients before you really can draw conclusions.”

Both the 25 percent and 50-50 mixtures improved depression in 17 of the participants. Researchers also discovered the benefits lasted longer after breathing in the more potent nitrous mixture. However, the 25 percent mixture resulted in fewer negative side-effects, such as nausea, vomiting, and headaches.

“Some patients experience side effects — it’s a small subset, but it’s very real — and the main one is that some people get nauseated,” Conway adds. “But in our study, only when people got the 50% dose did they experience nausea. When they received 25% nitrous oxide, no one developed nausea. And that lower dose was just about as effective as the higher dose at relieving depression.”

Laughing gas treatments lead to noticeable mental health improvements

Out of the 20 participants who completed the study and follow-up exams, 55 percent said the gas had “significantly improved” their depression symptoms. Moreover, researchers say 40 percent of the participants saw their depression go into remission.

Also, 85 percent of participants experienced enough improvement for doctors to lower their clinical classification by at least one category — going from severe to moderate, for example. Most of the patients continued taking antidepressants for the duration of the trial, even though they had largely failed to relieve their depression.

Laughing gas is a common tool dentists and surgeons use as a sedative. However, more people are increasingly using it as a recreational drug, inhaling it through balloons. In the United States, nitrous oxide is legal to possess, but the Food and Drug Administration regulates its use. Additionally, many states have their own laws which further regulate its sale and use. Ketamine, another anesthetic, has also been approved for treating depression by the FDA.

“One potential advantage to nitrous oxide, compared with ketamine, is that because it’s a volatile gas, its anesthetic effects subside very quickly,” Conway concludes. “It’s similar to what happens in a dentist’s office when people drive themselves home after getting a tooth pulled. After treatment with ketamine, patients need to be observed for two hours following treatment to make sure they are OK, and then they have to get someone else to drive them.”

Study authors note comparing the benefits of both treatments in a large study should be the next step.

The findings appear in the journal Science Translational Medicine.

SWNS writer Tom Campbell contributed to this report.

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