Hyperbaric oxygen therapy (HBOT) involves breathing oxygen in a pressurized chamber in which the atmospheric pressure is raised up to three times higher than normal. Under these conditions, your lungs can gather up to three times more oxygen than would be possible breathing oxygen at normal air pressure (from the FDA).
Hyperbaric chambers are medical devices subject to FDA approval. HBOT has not been approved for use in autism (or most of the other conditions it is purported to treat). This means HBOT has not been clinically demonstrated to be a safe and effective treatment for autism. As with many treatments, the claims made regarding the effectiveness of HBOT are not grounded in evidence.
HBOT is approved by the FDA for thirteen conditions, including air or gas embolism, carbon monoxide poisoning, decompression sickness and burns caused by heat or fire. While off-label use (the use of a drug or medical device for an indication other than what it is approved for) is not necessarily a problem, it does demand a higher level of scrutiny in considering the risks and benefits of the off-label use.
In 2013, the FDA issued a warning about HBOT in general and, in 2014, warning about the use of a variety of unproven therapies, including HBOT, for autism. In this warning, they provide tips to recognize false or misleading claims.
Be suspicious of products that claim to treat a wide range of diseases.
Personal testimonials are no substitute for scientific evidence.
Few diseases or conditions can be treated quickly, so be suspicious of any therapy claimed as a “quick fix.”
So-called “miracle cures,” which claim scientific breakthroughs and secret ingredients, may be a hoax.
The bottom line is this—if it’s an unproven or little known treatment, talk to your health care professional before buying or using these products.
The 2013 FDA warning mentioned above is discussed in more detail in this article, FDA Warns Consumers about Common Off-Label Autism Therapy, by Emily Willingham.
A 2015 review, Using hyperbaric oxygen for autism treatment: A review and discussion of literature, found only weak evidence supporting the use of HBOT in ASDs with only one flawed randomized control study showing a benefit and concluded that HBOT should not be recommended for ASDs without further study with well-designed trials.
The one study mentioned above that showed a benefit was published in 2009 been critiqued here by Steven Novella. The main criticisms are:
- Inadequate blinding of subjects and parents: “The primary weakness, in my opinion, is that the parents of the children being studied were allowed in the chamber with their children. The two groups in the study either received 24% oxygen in 1.3 atmospheres, or 21% oxygen in 1.03 atmospheres. It’s probable that many of the parents knew if they were getting increased pressure or not, and this therefore could have unblinded the study.”
- Small size of the study: “The study is also on the small side, with 62 children total. However, the clinical effects were very robust.”
- Potential conflicts of interest: More than one author of the study has a potential financial conflict of interest. Rossignol and Usman offer HBOT in their practice and Usman’s husband sells the hyperbaric chambers used for HBOT. “While such conflicts are important to expose, I think they are trumped by a well-enough controlled study. The whole point of a well-designed study is to eliminate the effects of bias. But given that this study was poorly blinded, and bias was present, it certainly diminishes its impact.”
- Only measured short term outcomes: It therefore did not test if the effect of hyperbaric treatment survives much beyond the treatment itself. Even if the effect in this study is real, it may represent only a temporary symptomatic benefit – not altering the course of autism itself. Therefore longer followup studies are needed as well.
It is not impossible that hyperbaric oxygen may have some benefit in some children with autism. Although there is no established mechanism at this time, and proposed mechanisms (like the notion that hyperbaric O2 decreases inflammation) are largely speculative. But a physiological effect is not implausible. The treatment is also fairly safe. Therefore it is reasonable to study it further.
The biggest risk of the treatment now is that it is expensive – costing 150-900 dollars per treatment or 14-17 thousand dollars for a chamber. It also diverts energy and emotions away from possibly more productive treatments.
An earlier systematic review from 2012, also found inconsistent results in the only two randomized and blinded trials.
While some uncontrolled and controlled studies suggested that HBO therapy is effective for the treatment of autism, these promising effects are not replicated. Therefore, sham-controlled studies with rigorous methodology are required to be conducted in order to provide scientific evidence-based HBO therapy for autism treatment.
A 2012 article on Left Brain Right brain critiques the scientific rationale for using HBOT in autism and discusses numerous studies exploring the scientific questions raised by using HBOT.