Hyperbaric oxygen for autism: this Cochrane review found no clear benefit

In one sentence

This Cochrane review found no reliable evidence that hyperbaric oxygen therapy helps core autism symptoms, based on one small trial of 60 children.

What the researchers did

The review looked at hyperbaric oxygen therapy, often called HBOT, as a possible support for autistic children. In HBOT, a person breathes oxygen inside a chamber where air pressure is higher than usual. Some families had hoped this might improve brain function or reduce autism-related difficulties, but those ideas needed proper testing.

The Cochrane authors searched for randomised controlled trials, which are among the most trustworthy study designs for comparing treatments. They found only one study that met the review criteria. That trial involved 60 children with autism spectrum disorder.

In the study, children were randomly assigned either to receive hyperbaric oxygen therapy or to a comparison condition. The review focused on whether HBOT changed the main features of autism, such as social interaction, communication, and repetitive behaviour. The authors also looked for information on side effects and safety.

Because only one small trial was available, the review was already working with a very limited evidence base. That matters, because even when a single study reports a difference, small studies can give unstable results that do not hold up when larger trials are done later.

What they found

The main conclusion was simple: there was no evidence that HBOT improved the core symptoms of autism.

The review did not find convincing signs that the children who received HBOT had better outcomes in social communication or other central autism-related features than children in the comparison group. With only 60 participants, the study was too small to give a confident answer about whether any real benefit exists.

The authors also reported minor side effects linked to the treatment. In particular, some children experienced ear barotrauma, which means pressure-related discomfort or minor injury in the ear when pressure changes inside the chamber. This is a known risk of hyperbaric treatment and is important for families to weigh, especially when there is no clear evidence of benefit.

So the overall picture was not "promising but unproven." It was weaker than that: there simply was not evidence from this review that HBOT helps with autism's core features, while there was at least some evidence of mild harm.

What this means for families and therapists

For families considering HBOT, this review suggests caution. Hyperbaric oxygen therapy can be expensive, time-consuming, and hard for some children to tolerate, especially if they are sensitive to enclosed spaces, noise, pressure changes, or unfamiliar routines.

When a treatment is demanding in those ways, it is reasonable to ask two questions: does it help, and what are the downsides? In this review, the answer to the first question was no clear evidence of help, and the answer to the second was that side effects, though minor, did occur.

That does not prove HBOT can never help any individual child. But it does mean families and professionals should not talk about it as an evidence-based way to improve the core features of autism. If it is being considered at all, decisions should be made carefully and with realistic expectations.

Limitations and what we don't know yet

The biggest limitation is that the review found only one small randomised trial. That is far too little evidence to support strong claims either way.

We also do not know whether certain subgroups of autistic children might respond differently, because the available study was too small to explore that question properly. Long-term outcomes were also unclear.

Future research would need to include larger, well-designed trials with clear outcome measures and careful reporting of side effects. Until that happens, there is no good evidence that HBOT improves the main difficulties associated with autism.

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This is a simplified summary of Hyperbaric oxygen therapy for people with autism spectrum disorder (ASD) by Xiong T, Chen H, Luo R et al., Cochrane Database of Systematic Reviews (2016).

Source license: CC-BY-NC-4.0.

This is not medical advice. Please consult a qualified healthcare professional before making therapy decisions.