You’re going to therapy. You’re exercising, sleeping better, and cutting out alcohol. You’ve tried medication. And yet something still isn’t right – a persistent fog, an anxiety that won’t settle, a mood that dips without warning. For a growing number of people in exactly this situation, the next question is whether the problem lies deeper than habits or mindset. Whether it’s happening at the level of the brain itself.
That’s where oxygen-based therapies have begun to receive serious scientific attention. Hyperbaric oxygen therapy, or HBOT, has existed for decades as a treatment for decompression sickness in divers and wound healing in clinical settings. But a wave of recent research – from randomised controlled trials to multi-year cohort studies – is now examining what HBOT does for the brain. The results are turning heads, particularly in the areas of PTSD, traumatic brain injury, and cognitive recovery.
This article breaks down what HBOT is, what the current evidence shows, and how some people are incorporating it as part of a broader mental wellbeing strategy. It’s not a replacement for professional care. It’s a conversation worth having.
What is hyperbaric oxygen therapy?
HBOT involves breathing 100% pure oxygen inside a pressurised chamber – typically at one and a half to three times normal atmospheric pressure. That elevated pressure does something ordinary breathing can’t: it forces oxygen to dissolve directly into the blood plasma, not just bind to red blood cells. This means oxygen reaches tissues that have become depleted – areas starved by injury, inflammation, or poor circulation.
The therapy was originally developed to treat nitrogen narcosis and decompression sickness in deep-sea divers. Clinicians noticed a side effect, though: it seemed to help wounds heal faster. That observation opened a decades-long research thread into how hyperoxygenation affects damaged or struggling tissue, including brain tissue.
Specifically in the brain, HBOT appears to do several things at once. It promotes neuroplasticity – the brain’s ability to form new connections and reorganise itself. It reduces neuroinflammation, which is increasingly understood as a driver of mood disorders and cognitive symptoms. It improves cerebral blood flow and supports mitochondrial function, meaning brain cells get more fuel to do their work.
A typical clinical protocol involves 40 to 60 sessions, each lasting 60 to 90 minutes. That’s a meaningful time and cost commitment, which is why some individuals explore more accessible options. For people researching how to incorporate oxygen therapy outside of a clinic, a home hyperbaric chamber can be one way to explore lower-pressure protocols – though clinical guidance matters when deciding what’s appropriate.
HBOT and PTSD – what the research shows
PTSD is notoriously hard to treat. Roughly two-thirds of veterans diagnosed with the condition still live with significant symptoms despite having tried multiple interventions – a figure from background data in a 2024 trial published in The Journal of Clinical Psychiatry. That’s not a small gap. It’s the reason researchers are looking beyond standard protocols.
That same 2024 trial is worth examining closely. It was randomised and sham-controlled, meaning participants were divided into real HBOT and a convincing placebo condition. The results were striking: 68% of HBOT participants showed at least a 30% reduction in PTSD symptoms, compared to only 4% in the control group. Perhaps more notably, 39% of HBOT patients achieved complete symptom remission – compared to 0% in the placebo arm. Participants completed 60 daily sessions at 100% oxygen at 2 ATA.
Brain imaging added depth to those numbers. Resting-state fMRI scans showed increased functional connectivity in the frontoparietal and default mode networks – two systems critical to emotional regulation, self-referential thinking, and cognitive control. The therapy wasn’t just quieting symptoms. It appeared to be reorganising how affected brain regions communicate.
These findings align with a 2024 systematic review published in Frontiers in Neurology, which analysed 8 studies involving 393 subjects across a range of HBOT protocols (1.3 to 2.0 ATA; 40 to 60 sessions). Statistically significant improvements were observed across the board, and the majority of patients maintained benefits at two-year follow-up, including reduced medication use and improved social and occupational functioning.
The honest gap: larger trials with longer follow-up periods are still needed. HBOT isn’t a first-line PTSD treatment, and it probably won’t replace trauma-focused therapy or psychiatric care for most people. But for those who haven’t responded adequately to standard approaches, these numbers deserve attention. If you’re already thinking about holistic approaches to mental wellbeing alongside conventional therapy, HBOT fits that same evidence-backed complementary framework.
Depression, anxiety, and brain fog – what else does HBOT affect?
The PTSD data gets the most attention, but the 2024 Journal of Clinical Psychiatry trial also captured something interesting outside of PTSD symptom scores. Participants reported notable reductions in depressive symptoms and drops in self-reported stress and anxiety levels – even though those weren’t the primary endpoints. That’s a meaningful secondary finding.
Some of this may connect to neuroinflammation. There’s a growing body of research linking elevated inflammatory markers to depression and anxiety that doesn’t respond to antidepressants. If HBOT reduces neuroinflammation, that could offer a biological explanation for why some people see mood improvements alongside cognitive ones. The evidence here is earlier-stage, but the mechanism is plausible and increasingly studied.
The brain fog picture is clearer for people with a history of head injury. A 2025 meta-analysis published in Neurology examined 250 patients with traumatic brain injury and found that HBOT produced significant improvements in general cognitive scores, memory, attention, executive function, and information processing speed. These weren’t small effect sizes – the memory finding alone reached a mean difference of 10.13 (p < 0.00001).
What’s striking about a separate 2025 study in Frontiers in Neurology is the timing. This retrospective cohort followed adults who had experienced TBI in childhood – meaning their original injuries were decades old. After at least 40 sessions of HBOT (90 minutes, 100% oxygen at 2 ATA), they showed statistically significant improvements across all cognitive domains, with effect sizes ranging from r = 0.62 to 0.78. The brain, even after years, appears to retain some capacity to respond.
This matters for everyday mental health conversations because TBI and subclinical brain injuries are far more common than most people realise. Cognitive symptoms – brain fog, attention difficulties, mood swings – often get attributed to anxiety or depression when an underlying neurological factor is actually driving them.
HBOT as a complement to mental health treatment, not a replacement
To be clear: HBOT is not a substitute for therapy, psychiatric evaluation, or professional mental health care. Anyone who tells you otherwise is overselling the research. What HBOT represents is a complementary tool – one that works at a biological level and may help when other approaches have plateaued.
Think about how the field already treats adjunctive options. TMS (transcranial magnetic stimulation) is now mainstream as a complement to medication for treatment-resistant depression. Mindfulness-based programmes sit alongside CBT rather than replacing it. The logic for HBOT is the same: it’s targeting a different mechanism, not competing with approaches that address the psychological and relational dimensions of mental health.
Who is most likely to benefit? The current evidence points toward people with treatment-resistant PTSD, post-concussion symptoms, or those managing cognitive effects from head injury. For anxiety and depression without an identifiable neurological component, the evidence is early-stage, but enough to make it worth discussing with a qualified provider.
Practical considerations matter here, too. Clinical hyperbaric chambers operate at higher pressures than most personal units, which affects the conditions they can treat. Cost and time commitment for a full clinical protocol can be substantial. Before starting any HBOT regimen, a conversation with your physician or mental health provider is the right first step – not because HBOT is particularly risky at mild pressures, but because informed decisions lead to better outcomes. Research into nature therapy for mental health shows that the most effective complementary tools are often simpler than people expect – and knowing which ones fit your situation is exactly where a qualified provider can help.
Building a holistic brain health routine
HBOT doesn’t work in isolation. The strongest outcomes in the research come from people who are also engaged with sleep hygiene, physical activity, stress management, and professional support. Oxygen therapy can support the brain’s healing capacity, but it can’t compensate for chronic sleep deprivation or unmanaged trauma. It’s a piece, not the whole picture.
A practical brain health routine might look something like this: regular therapy (whether CBT, EMDR, or another modality suited to your needs), consistent aerobic exercise a few times per week, a sleep schedule you actually protect, and an adjunctive tool – whether that’s HBOT, TMS, nature-based practice, or something else that fits your life and has evidence behind it. You don’t have to do all of this at once. Most people add one layer at a time.
The honest truth is that what works varies by person. Someone with treatment-resistant PTSD and a history of head injury might respond dramatically to HBOT. Someone managing generalised anxiety with no neurological component might see less change. That variability isn’t a reason to dismiss the therapy – it’s a reason to approach it with the same curiosity and realistic expectations you’d bring to any new tool.
If you’re not sure where to start or what options are actually available, exploring mental health treatment options is a useful first step toward building a plan that fits.
The brain can heal
Mental well-being isn’t one-dimensional. For many people, healing requires working at multiple levels simultaneously – the psychological and relational through therapy, the behavioural through lifestyle, and sometimes the biological through approaches that target the brain directly. HBOT is one of the more interesting developments in that third category.
The research isn’t finished. Larger trials are needed, and we’re still learning which people benefit most, which protocols work, and over what timeframe. But the evidence that exists – particularly for PTSD, TBI, and cognitive recovery – is meaningful enough to take seriously. These aren’t fringe studies. They’re randomised trials and systematic reviews in respected journals.
If you’ve been in treatment and still feel like something isn’t quite right, that’s worth talking about with your provider. Newer tools are being studied and made available all the time. The brain has more capacity to heal than we once believed, and finding the right combination of support is a process worth continuing.