HBOT for Veterans and Combat PTSD: The Research, the Programmes, and What It Means in Practice

Of all the populations being studied in hyperbaric oxygen research, military veterans with combat-related PTSD have received the most sustained and rigorous scientific attention. This is not coincidental. Veterans represent a population with a high prevalence of treatment-resistant PTSD, a well-documented pattern of neurobiological injury, and an urgent clinical need that existing treatments have not adequately met.

The research that has emerged from this focus is more substantial than most people outside the hyperbaric medicine community realise. It does not yet establish HBOT as a standard treatment for combat PTSD. But it does provide a credible, mechanistically coherent body of evidence that is attracting serious attention from researchers, clinicians, and military health institutions.

Why Combat PTSD Is Different

PTSD is not a single, uniform condition. The trauma profile of a combat veteran differs in important ways from civilian PTSD arising from accidents, assault, or medical trauma, and those differences have clinical implications.

Combat exposure typically involves repeated, prolonged trauma rather than a single event. It frequently involves physical injury alongside psychological trauma. And in modern warfare, it almost always involves exposure to blast events, whether from improvised explosive devices, artillery, or other explosive ordnance.

Blast exposure is significant because it causes a specific pattern of neurological injury that is distinct from the psychological effects of combat trauma. A blast wave generates a pressure transient that travels through the body and brain, causing diffuse axonal injury, microhaemorrhages, and disruption to the blood-brain barrier. This is mild traumatic brain injury (mTBI), and it is extraordinarily common in combat veterans. Studies of veterans who served in recent conflicts have found rates of blast-related mTBI ranging from 15 to 23 percent, with some estimates considerably higher when subclinical exposure is included.

The clinical significance of this is that many veterans presenting with PTSD are also carrying undiagnosed or underdiagnosed blast-related brain injury. The two conditions share overlapping symptoms, including sleep disturbance, irritability, cognitive difficulties, and emotional dysregulation, and they are frequently conflated in clinical assessment. A veteran who has been treated for PTSD for years without adequate response may be carrying a neurobiological injury that psychological treatment alone cannot address.

This is the population in which HBOT research has been most active, and it is the population in which the results have been most compelling.

The Neurobiological Basis for HBOT in Combat Veterans

The mechanisms by which HBOT may help veterans with PTSD and blast-related mTBI are well characterised in the research literature.

Blast injury and chronic PTSD both produce measurable reductions in cerebral blood flow in specific brain regions. SPECT and perfusion MRI imaging consistently show hypoperfusion in the prefrontal cortex, hippocampus, anterior cingulate cortex, and amygdala in affected veterans. These are the regions responsible for emotional regulation, threat assessment, memory consolidation, and the capacity to distinguish present safety from past danger. When these regions are underperfused, the neurological substrate for the core symptoms of PTSD, including hypervigilance, intrusive memories, emotional numbing, and exaggerated startle response, is directly implicated.

HBOT addresses this through several converging mechanisms. By dramatically increasing the partial pressure of dissolved oxygen in plasma, it delivers oxygen to tissues that are poorly perfused and metabolically compromised. It stimulates angiogenesis, the growth of new blood vessels, which can improve baseline cerebral perfusion over a course of treatment. It promotes neuroplasticity through upregulation of brain-derived neurotrophic factor (BDNF) and other growth factors. And it has well-documented anti-inflammatory effects that address the chronic neuroinflammation associated with both PTSD and blast injury.

The result, in imaging studies, is measurable improvement in cerebral blood flow in the regions most affected by combat trauma and blast injury. The clinical correlate of that improvement is reduction in PTSD symptom severity.

The Sagol Center Trials

The most rigorous and widely cited research on HBOT for combat PTSD has come from the Sagol Center for Hyperbaric Medicine and Research at Shamir Medical Center in Israel. The Sagol Center has been the leading institution in this field for over a decade, and its work with Israeli Defence Forces veterans has produced the most substantial evidence base currently available.

The landmark 2023 randomised controlled trial, published in the journal PLOS ONE, enrolled 35 veterans with treatment-resistant PTSD. Participants were randomised to either 60 sessions of HBOT at 2.0 ATA breathing 100% oxygen for 90 minutes per session, or a sham control condition. The HBOT group demonstrated significant reductions in PTSD symptom severity on the Clinician-Administered PTSD Scale (CAPS-5), the gold standard assessment tool for PTSD diagnosis and severity. Improvements were also observed in depression, anxiety, and quality of life measures. Brain perfusion imaging showed increased cerebral blood flow in the prefrontal cortex and other affected regions.

Critically, this was a trial in treatment-resistant patients. These were not veterans at the beginning of their treatment journey. They were individuals who had already engaged with standard care, including psychotherapy and medication, without achieving adequate relief. The fact that meaningful clinical improvements were observed in this population is the most significant finding in the trial.

Earlier work from the Sagol Center, published in 2014 in PLOS ONE, examined HBOT in veterans with blast-related mTBI and comorbid PTSD. That trial demonstrated improvements in both cognitive function and PTSD symptoms, with corresponding improvements in brain perfusion on SPECT imaging. The 2014 paper was among the first to provide imaging evidence that HBOT was producing measurable neurobiological change, not simply a placebo response.

A further study from the Sagol group, published in 2022, examined the neuroimaging correlates of HBOT response in veterans with PTSD, identifying specific patterns of baseline hypoperfusion that predicted treatment response. This work is significant because it points toward the possibility of imaging-guided patient selection, identifying in advance which veterans are most likely to benefit from HBOT based on their neurobiological profile.

United States Military Research

The United States Department of Defense and the Veterans Administration have both funded research into HBOT for veteran populations, reflecting institutional recognition that the existing evidence warrants serious investigation.

The DoD-funded HOPPS trial (Hyperbaric Oxygen for Post-concussive Symptoms) examined HBOT in veterans with persistent post-concussive symptoms following blast exposure. The trial, conducted across multiple military medical centres, found improvements in post-concussive symptoms and quality of life in the HBOT group, though the results were more mixed than the Sagol trials and generated significant methodological debate about the appropriate control condition for hyperbaric research.

The controversy around the HOPPS trial and related DoD-funded work is worth understanding. The central methodological challenge in hyperbaric research is the design of an adequate sham control. Participants in a pressurised chamber at even slightly elevated pressure with slightly elevated oxygen will experience some physiological effect, making a true placebo difficult to construct. Different research groups have used different sham conditions, and the choice of sham affects the apparent effect size. This does not invalidate the positive findings from well-designed trials; it means that the evidence base needs to be read carefully, with attention to methodology.

The VA has also supported research through its Cooperative Studies Program, and several VA medical centres have established hyperbaric programmes specifically for veteran populations. The integration of HBOT into VA care pathways remains limited and inconsistent, but the institutional interest is real and growing.

The Blast Injury and mTBI Connection

For veterans with both PTSD and blast-related mTBI, the case for HBOT is particularly well supported by the research literature. The two conditions share neurobiological mechanisms, and HBOT addresses both through the same pathways.

The clinical presentation of a veteran with comorbid PTSD and mTBI is often characterised by a symptom cluster that does not respond well to either standard psychiatric treatment or standard neurological rehabilitation in isolation. Cognitive difficulties, including problems with attention, memory, and executive function, sit alongside the emotional and psychological symptoms of PTSD in a way that makes the conditions difficult to disentangle and treat separately.

HBOT's capacity to improve cerebral perfusion, reduce neuroinflammation, and promote neuroplasticity addresses the neurobiological substrate of both conditions simultaneously. Several of the Sagol Center trials specifically enrolled veterans with comorbid PTSD and mTBI, and the results in this population have been among the most consistent in the literature.

For veterans who have been told that their cognitive symptoms are a consequence of PTSD, or that their PTSD symptoms are a consequence of brain injury, and who have not responded adequately to treatment targeting either condition in isolation, the possibility that both are expressions of the same underlying neurobiological injury, and that both may respond to the same intervention, is clinically significant.

What a Treatment Protocol Looks Like

The protocols used in the published research on combat PTSD have been consistent. The standard protocol involves 60 sessions at 2.0 ATA, breathing 100% oxygen, with each session lasting 90 minutes. Sessions are typically conducted five days per week, making the full course approximately 12 weeks.

This is a substantial commitment. For veterans who are working, managing family responsibilities, or dealing with the practical and logistical challenges that frequently accompany PTSD, 12 weeks of daily treatment is not a trivial undertaking. It requires access to a facility with genuine experience in treating veteran populations, and it requires a level of logistical support that not all veterans have.

The enclosed environment of a hyperbaric chamber presents a specific consideration for veterans with combat PTSD. Claustrophobia is not uncommon in trauma survivors, and the sensory environment of a pressurised chamber, including the pressure changes during compression and decompression, can be activating for some patients. Reputable facilities with experience in treating veterans will assess this carefully, will have protocols for managing anxiety in the chamber, and will work with the patient's existing mental health team to ensure that the treatment is delivered in a supported context.

For most veterans, the experience becomes more manageable over the course of treatment. But this is a conversation to have explicitly with the clinical team before committing to a course, and it is one of the reasons why the quality of clinical oversight matters so much in this population.

The Relationship with Existing Mental Health Care

HBOT for combat PTSD should not be pursued as a replacement for psychological treatment. The research protocols that have produced the most significant results have been conducted in the context of coordinated care, where HBOT is one component of a broader treatment approach.

The neurobiological improvements that HBOT may produce, including improved cerebral perfusion and reduced neuroinflammation, can create conditions in which psychological treatment becomes more effective. Veterans who have been unable to engage productively with trauma-focused therapy because of the severity of their symptoms may find that a course of HBOT changes what is possible in the psychological domain.

This is not a claim that HBOT replaces therapy. It is an observation that the neurobiological and psychological dimensions of combat PTSD are not independent, and that addressing the neurobiological dimension may open doors that were previously closed.

Facilities that treat veterans with PTSD in isolation from their existing mental health providers are not providing the standard of care that this population requires. The relationship between the hyperbaric team and the veteran's broader care network is a meaningful indicator of the quality of the programme.

What Veterans Should Know Before Pursuing Treatment

The evidence for HBOT in combat PTSD is more substantial than in most other emerging applications of hyperbaric medicine. It is not yet sufficient to establish HBOT as a standard treatment, and it should not be presented as a guaranteed outcome. But for veterans who have engaged seriously with conventional treatment without adequate relief, it represents a credible option with a coherent evidence base and a reasonable safety profile.

The questions worth asking when evaluating a facility include: does the facility have specific experience treating veterans with PTSD and blast-related mTBI; what protocol do they use and how does it compare to the published research; how do they coordinate with existing mental health providers; what is their approach to managing the chamber environment for patients with trauma histories; and what outcomes have they observed in their veteran patient population.

The answers to these questions will vary considerably between facilities. Some hyperbaric centres have developed genuine expertise in treating veteran populations and have the clinical infrastructure to support them appropriately. Others offer HBOT as a general service without the specific experience that this population requires.

Understanding the difference is part of making an informed decision.