Your body didn’t forget the war—no matter how much you might have wanted to. For many Veterans living with post-traumatic stress disorder (PTSD), the symptoms don’t stop at nightmares or hypervigilance. They show up at the dinner table, in the middle of the night, in every cramped bathroom and canceled plan. Irritable bowel syndrome (IBS) affects numerous Veterans with PTSD, yet the U.S. Department of Veterans Affairs (VA) routinely undervalues or outright denies claims that connect the two conditions. That denial doesn’t make the pain less real, and it doesn’t have to be the end of the road.
The Law Office of Sean Kendall has spent decades helping Veterans across the country fight for the benefits they’ve earned through service. With a practice built on understanding how the VA evaluates complex, overlapping conditions, Sean Kendall and his team bring both legal skill and medical knowledge to cases where the connection between service and suffering isn’t always obvious, but is always worth pursuing. Read on to learn more about how the process works, then contact us with any questions and to discover how we help Veterans throughout the U.S. receive their rightful benefits.
Why Does PTSD Cause IBS in Veterans?
It has to do with the gut-brain axis and how chronic stress affects your digestive system. Most people think of PTSD as a condition of the mind. The reality is more physical—and more far-reaching. PTSD keeps the body’s stress response in a near-constant state of activation. The nervous system stays on high alert, and that sustained state of hyperarousal doesn’t just affect mood, sleep, or cognition. It directly disrupts the way the gut functions.
The gut and the brain communicate through a bidirectional network called the gut-brain axis. In a healthy system, signals move in both directions, and intestinal motility stays regulated. In someone living with PTSD, chronic activation of the autonomic nervous system throws that regulation off. The intestines may contract too quickly or too slowly. Visceral sensitivity increases, meaning sensations that wouldn’t normally be painful become consistently uncomfortable. The result—cramping, bloating, alternating diarrhea and constipation, and persistent abdominal pain—maps directly onto the diagnostic profile for IBS.
Medical research consistently identifies PTSD as one of the strongest psychological risk factors for functional bowel disorders. This isn’t a theoretical association. It’s a documented physiological pathway with a clear mechanism.
When Alcohol Use Disorder Enters the Picture
For Veterans whose PTSD co-occurs with alcohol use disorder (AUD)—a common and well-documented combination—the gastrointestinal effects compound. Alcohol irritates the lining of the digestive tract, disrupts normal gut motility, alters the intestinal microbiome, and increases what researchers call intestinal permeability. Chronic use produces persistent bowel irregularity, abdominal sensitivity, and discomfort that closely mirrors IBS symptoms.
When both conditions are present, the combined effect on the gut isn’t just addictive—it creates a direct and clinically coherent physiological pathway for IBS development. This matters for VA claims because it means that real medical evidence can establish the connection between service-related PTSD, any co-occurring AUD, and a subsequent IBS diagnosis.
What Does the VA Require to Approve a Secondary Service Connection?
Secondary service connection allows Veterans to receive disability compensation when an already service-connected condition causes or aggravates another condition. For Veterans with service-connected PTSD, IBS can qualify—but the VA won’t simply assume the connection exists. The burden falls on the Veteran to establish it. To approve a secondary service connection for IBS, the VA generally looks for:
- A current IBS diagnosis. A formal diagnosis from a qualified medical provider documents that the condition exists and is active.
- An existing service-connected condition. The VA must already recognize your service-connected PTSD before it can serve as the basis for a secondary claim.
- A medical nexus linking the two. This is where many claims run into trouble. The VA requires a medical opinion—typically from a physician or specialist—explaining how PTSD caused or worsened the IBS. Without this nexus opinion, denials are common.
- Supporting medical evidence. Treatment records, physician notes, and any documentation of gastrointestinal symptoms that align with the PTSD timeline all strengthen the claim.
Understanding the Importance of an Effective Nexus Letter
The nexus letter is often the most critical piece of the entire claim. A well-constructed opinion that explains the gut-brain axis, cites relevant medical literature, and ties the Veteran’s specific symptom history to their PTSD diagnosis can be the difference between approval and denial.
Not all nexus letters carry equal weight with the VA. A letter that simply states a connection exists—without explaining the reasoning behind it—is unlikely to move the needle. The most effective nexus letters are detailed, clinically grounded, and written by a physician who understands the condition and how the VA evaluates medical evidence.
The single most important phrase in any nexus letter is “at least as likely as not.” This is the legal standard the VA uses to evaluate medical opinions, and it reflects a 50% or greater probability that the claimed condition is related to the service-connected diagnosis. A physician who doesn’t use this language—or who uses softer phrasing like “possibly related” or “could be connected”—may inadvertently fall short of the threshold the VA requires. The language has to be explicit.
Beyond that phrase, a strong nexus letter should walk through the medical mechanism. For IBS secondary to PTSD, that means explaining how chronic activation of the stress response disrupts the gut-brain axis, alters intestinal motility, and produces the specific symptoms the Veteran experiences. When AUD is also present, the letter should address that pathway as well, including how the disorder itself may be traceable to PTSD, extending the chain of causation back to military service. A well-constructed letter doesn’t just assert a conclusion: it shows the VA exactly how the physician determined it.
Why Do So Many IBS Secondary Claims Get Denied?
Unfortunately, the VA’s evaluation process doesn’t always reflect current medical science. IBS is classified as a functional gastrointestinal disorder, meaning it produces real symptoms without a structural cause that appears in imaging or standard diagnostic tests. That distinction creates problems in the VA claims process, where examiners who aren’t specialists in gastroenterology or psychological medicine may not fully appreciate how PTSD drives functional GI conditions.
Denials often come down to one of several recurring problems:
- Inadequate or missing nexus opinion. The VA-ordered compensation and pension exam might not adequately address the PTSD-IBS connection, and Veterans without independent medical opinions are left with a gap in the record.
- Failure to account for alcohol use disorder. When AUD co-occurs with PTSD, examiners sometimes attribute GI symptoms to alcohol alone, without recognizing that the disorder itself may be secondary to PTSD, creating a traceable chain of causation back to military service.
- Underrating of IBS symptoms. Even when IBS is service-connected, the VA’s rating schedule for digestive conditions may not fully capture the functional impact of symptoms like unpredictable bowel habits, chronic pain, and the limitations they place on daily life and employment.
What Can Our Veterans Disability Lawyer Do That the VA Won't?
For decades, Sean Kendall, Attorney at Law, has handled VA claims across the country, appearing before all current judges of the U.S. Court of Appeals for Veterans Claims. Our team has handled cases involving psychiatric and physical conditions that intersect in exactly the ways that PTSD and IBS do. This kind of experience matters when a claim requires medical sophistication, not just legal paperwork.
Working with our Veterans disability lawyers means having someone who can identify gaps in the record before a denial happens, coordinate with qualified medical professionals to develop a strong nexus opinion, and pursue appeals through the Board of Veterans’ Appeals or the Court of Appeals for Veterans Claims when the VA gets it wrong the first time.
Veterans with service-connected PTSD who are also living with IBS have a medically sound, legally pursuable path to additional benefits. The science supports the connection. The law provides the mechanism. Winning requires building the claim the right way and knowing where the VA is likely to push back.
Whether you’re filing a claim for the first time or you received a denial from the VA, the Law Office of Sean Kendall provides sound representation and guidance to help you navigate the process.
