Hyperbaric – or high-pressure – oxygen therapy (HBOT) has for many decades been used to treat decompression sickness – a potential risk of scuba divers who rise to the surface too fast. Since then, it has been utilized for treating serious infections in which tissues are starved for oxygen, gangrene and wounds that do not heal such as in the legs of diabetics, burns and radiation injury, as well as for saving victims of carbon monoxide poisoning. HBOT has also been reported to improve post-concussion syndrome years after mild traumatic brain injury

More recently, a research team at Tel Aviv University announced a world breakthrough – using HBOT to restore brain trauma that was proven effective in preventing the core biological processes responsible for the development of Alzheimer’s disease. 

A major limitation of hyperbaric oxygen treatment is its high cost—it requires a special chamber which is expensive and available only in select major medical centers around the world. The treatment process is of approximately an hour duration requiring patients to travel to a specific, often remote, location. In addition, it can have severe side effects if the pressure rises too quickly or decreases too rapidly. 

But now, scientists at Ben-Gurion University (BGU) of the Negev have revealed that oxygen treatment can accomplish something completely different – depressed patients who received oxygen-enriched air treatment for a month found their symptoms improved, according to a new proof-of-concept study by the Beersheba researchers. Given the obstacles surrounding hyperbaric oxygen treatment, the team hypothesized the possibility that normobaric oxygen treatment may serve as a useful and attractive treatment strategy for depression.

Their findings have just been reported in Scientific Reports under the title “Normobaric oxygen treatment for mild-to-moderate depression: a randomized, double-blind, proof-of-concept trial.” 

Normobaric is air pressure at sea level (35% to 40% oxygen), considerably lower than the hyperbaric (100% oxygen) used for the other medical conditions. On the other hand, the use of hyperbaric oxygen was found to reduce blood flow in the cerebrum of the brain. The oxygen was administered under normal atmospheric conditions, which avoided the inherent dangers of hyperbaric chambers.

The air in Earth’s atmosphere that we breathe is made up of about 78% nitrogen and 21% oxygen. Normally, oxygen can make its way through the blood only within red blood cells. When these blood cells are too low or can’t circulate properly, important tissues become deprived of oxygen.

Depression is a devastating mental illness causing immense suffering among affected subjects and their families and is associated with severe emotional, functional and financial burden. It is especially common among women, with a life-time prevalence ranging between 10% and 20% in the general population. But actual numbers may be even higher, given the cultural-associated differences in diagnosing mental illness.

The most widely used treatment strategies for depression are medications, electroconvulsive therapy and cognitive behavioral therapy. However, despite the availability of therapeutic approaches, a high percentage of subjects with depression respond poorly or not at all to these treatments, with considerable amounts of them suffering from unwanted side effects. 

As few new therapeutic interventions have been developed and introduced to clinical practice for the treatment of depression in recent years, they wrote, these data reinforce the need for a relentless search for a new, effective and safe treatment options for depression.

The 55 patients including people who directly contacted the researchers expressing interest in participating in the study following advertisements in the public media and subjects from Clalit Health Services, Israel’s largest health maintenance organization. They were divided into two groups living in the country’s southern district. The first group of people were treated with oxygen-enriched air (35% oxygen) and the other with room/normal air (21% oxygen) for seven to eight hours per night over the course of four weeks. After treatment, the researchers found that depressive symptoms were reduced on several measurement scales.

“As a proof-of-concept, our results are promising. Increasing the fraction of oxygen in the inhaled air reduces symptoms of depression,” said lead researcher Dr. Abed N. Azab, a member of the nursing department of in BGU’s Faculty of Health Sciences.

“Of course, there is much more to discover. Would longer treatments be even more beneficial? Would higher oxygen concentrations better improve symptoms or not? Importantly, the administration of oxygen was safe and did not cause adverse effects,” he concluded.