FND in Veterans: What Military Service Members and Their Families Need to Know

Veterans are diagnosed with Functional Neurological Disorder at rates significantly higher than the general civilian population. The reasons are neurological, not incidental. Military service creates a specific constellation of risk factors, including traumatic brain injury, blast exposure, chronic high-stress nervous system activation, and PTSD, that interact with the brain network mechanisms underlying FND in documented ways. For families supporting veterans with unexplained neurological symptoms, understanding this connection changes how they interpret what they are seeing and what they can advocate for.

This article covers what the research shows about FND in military populations, how it overlaps with TBI and PTSD, what the diagnostic challenges are in the VA system, and what VA benefits apply when FND is service-connected.

How Common FND Is in the Military Population

A military epidemiology study published in Medical Surveillance Monthly Report analyzed FND incidence across the U.S. Armed Forces from 2000 to 2018. The overall incidence rate was 29.5 per 100,000 person-years, approximately 2.5 times higher than the general population rate. Among service members with a history of PTSD or depression, the rate was 10 times higher than in those without those diagnoses.

A 2025 clinical review published in Primary Care Companion for CNS Disorders by Rustad, Hodges, DeSimone, and colleagues from Dartmouth, Naval Medical Readiness Training Command, and multiple VA facilities examines FND specifically in active-duty and veteran populations. The authors note that FND commonly co-occurs with depression, anxiety, PTSD, and other functional somatic disorders in this population, and that the military context creates specific diagnostic and treatment challenges that civilian-trained clinicians may not be equipped to navigate.

Why Military Service Increases FND Risk

FND develops from the interaction of predisposing, precipitating, and perpetuating factors acting on brain network function. Military service concentrates several of the most significant precipitating and perpetuating factors into a single service member's history.

Traumatic Brain Injury

TBI is both a precipitating factor for FND and a condition that can mask FND symptoms or make diagnosis more difficult. When a veteran has a documented TBI history, new or persistent neurological symptoms are often attributed to the TBI without adequate evaluation for FND as a separate or co-occurring condition. A 2024 study in Frontiers in Neurology examining functional connectivity in 181 Iraq and Afghanistan combat veterans found that deployment TBI, blast exposure, and PTSD each contributed independently to differences in brain network function, with long-term symptom presentation persisting an average of 9.4 years after deployment. The brain network disruptions documented in that study overlap directly with the mechanisms implicated in FND.

For families, the practical implication is that a veteran with a TBI diagnosis who continues to have neurological symptoms beyond the expected recovery window may be experiencing FND as a separate condition that deserves its own evaluation, not just a continuation of TBI sequelae.

Blast Exposure

Blast exposure creates neurological effects that are distinct from direct impact TBI and not fully captured by standard imaging. Research published in Frontiers in Neurology documents that blast exposure is associated with alterations in brain structure and function, reduced white matter integrity, and changes in cognitive performance, independent of whether a formal TBI diagnosis was made. These changes affect the same brain networks involved in FND pathophysiology.

Many veterans with significant blast exposure histories do not have a documented TBI diagnosis because they did not seek evaluation at the time or because their symptoms did not meet the threshold for a formal diagnosis. This means their neurological history may be underrepresented in their medical record, which complicates both FND diagnosis and VA service connection claims.

PTSD and Chronic Stress

PTSD is one of the strongest documented risk factors for FND in the veteran population, with the rate of FND among veterans with PTSD running approximately 10 times higher than in those without. This is not because PTSD causes FND through psychological mechanisms alone. PTSD involves documented changes in the limbic system, the prefrontal cortex, and the stress response systems that directly affect brain network communication. The same network dysregulation that underlies PTSD symptom patterns interacts with the predictive coding mechanisms implicated in FND.

A 2025 systematic review protocol published in BMJ Open examining PTSD, complex PTSD, and FND comorbidity estimates that comorbid psychiatric diagnoses are present in 51 to 95 percent of FND patients across studies. For veterans, where PTSD prevalence is substantially higher than in the general population, this overlap is clinically significant and frequently missed.

Diagnostic Challenges in the VA System

The 2025 Rustad et al. review in Primary Care Companion for CNS Disorders identifies the VA system as presenting specific challenges for FND diagnosis and treatment. FND training is inconsistent across VA facilities. Clinicians who see veterans with complex multi-diagnosis profiles including TBI, PTSD, chronic pain, and neurological symptoms may not recognize FND as a distinct condition requiring its own positive diagnostic criteria. Symptoms may be attributed entirely to PTSD or TBI without adequate neurological evaluation.

Veterans themselves may resist a functional neurological diagnosis if it is presented in a way that feels dismissive of their service-related injuries. The history of functional diagnoses being used to deny or minimize legitimate neurological conditions in military contexts creates understandable skepticism. For this reason, how the diagnosis is delivered matters enormously in this population. A clear, non-blaming explanation grounded in neurobiological mechanisms is more likely to result in treatment engagement than a framing that implies psychological causation.

VA Disability Benefits and Service Connection for FND

FND is a condition for which VA service connection and disability compensation can be established. The 2025 Rustad et al. review confirms that for a condition to be awarded service connection and disability compensation, the veteran's current disability must be linked to an incident in military service that either caused or worsened the condition, and that FND is explicitly one of these conditions.

Service connection for FND can be established through several pathways. A direct service connection argument links FND onset to a specific in-service event such as a TBI, blast exposure incident, or documented period of high stress. A secondary service connection argument links FND to another already service-connected condition such as PTSD or TBI. An aggravation argument applies when a pre-existing FND condition was worsened by military service.

Veterans and families pursuing a VA claim for FND benefit from having a nexus letter from a treating neurologist or neuropsychiatrist that explicitly connects the FND diagnosis to military service history. Documentation of the positive clinical signs used to confirm the FND diagnosis, the treatment history, and the functional limitations the condition imposes on daily life all strengthen a claim. Working with an accredited VA claims agent or Veterans Service Organization representative is advisable when navigating this process.

Treatment for Veterans with FND

The evidence-based treatment approaches for FND in the general population apply to veterans, with the additional consideration that PTSD, TBI sequelae, and chronic pain frequently need to be addressed simultaneously. FND-specific physiotherapy remains the primary intervention for motor symptoms. CBT adapted for trauma contexts is more appropriate than standard CBT when significant PTSD is present.

The VA system has specialist neurology and neuropsychiatry resources at major medical centers, and FND-informed care is available at some facilities, though not uniformly. Families advocating for a veteran with FND can request a referral to neurology for a formal evaluation using positive clinical signs, and can ask specifically whether the evaluating clinician has experience with FND diagnosis and treatment.

For a full overview of evidence-based FND treatment options, see our article on FND treatment options. For practical guidance on communicating with medical teams and supporting a veteran with FND day to day, see the FND Caregiver Communication Guide.

Educational content only. Robbins Nest Alliance does not provide medical, legal, or VA claims advice. Content references peer-reviewed research including Medical Surveillance Monthly Report, Primary Care Companion for CNS Disorders, Frontiers in Neurology, BMJ Open, and Neurotherapeutics. Veterans pursuing VA disability claims should work with an accredited claims agent or Veterans Service Organization representative.