Nitrous oxide or laughing gas could be used as a treatment for severe depression in patients whose symptoms don't respond to normal therapies.
According to a pilot study conducted at Washington University School of Medicine in St. Louis, which is believed to be the first research, patients with depression were given laughing gas and the results showed early promises of treating depression.
In 20 patients who had treatment-resistant clinical depression, the researchers found that two-thirds experienced an improvement in symptoms after receiving nitrous oxide. In comparison, one-third of the same patients reported improved symptoms after treatment with a placebo. The patients were evaluated on the day of and day after each treatment.
As part of the study, patients received two treatments, but neither the subjects nor the researchers knew the order in which those treatments were given. In one session, patients were given a gas mixture that was half oxygen and half nitrous oxide - the same mixture dentists give to patients undergoing dental procedures. In a second session, the patients received a placebo mixture of oxygen and nitrogen, the two main gases in the air we breathe.
The study subjects were surveyed about the severity of their symptoms, such as sadness, feelings of guilt, suicidal thoughts, anxiety and insomnia. One day after nitrous oxide treatment, seven patients reported mild improvement in their symptoms, while another seven reported significant improvement. Three patients reported that their symptoms had disappeared almost completely. No patients said their symptoms worsened after treatment with nitrous oxide.
Meanwhile, after receiving the placebo, one patient reported worse symptoms the next day, five reported mild improvements, and two reported that they felt significantly better.
Co-investigator Charles R. Conway, MD, said that when the patients received nitrous oxide, many of them reported a rapid and significant improvement.
The researchers said more studies were needed to learn whether nitrous oxide had the same benefits in other patients with depression. They also plan to test various concentrations of laughing gas to see how each influences symptoms of depression.
The findings were published online in the journal Biological Psychiatry.