Many veterans have recently come across videos and discussions suggesting that secondary VA claims have become more difficult to win. Much of the concern stems from legal terminology that was clarified by the courts and later incorporated into VA guidance. As a result, some veterans worry that the rules have changed and that obtaining secondary service connection is now more challenging.
The reality is more nuanced. According to legal experts familiar with VA disability law, recent developments are intended to clarify existing standards rather than raise the burden of proof for veterans.
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Understanding Secondary VA Claims
Secondary service connection allows veterans to receive disability benefits for conditions that develop because of an already service-connected disability.
For example:
- A service-connected knee injury leads to an altered gait and later causes hip problems.
- Service-connected depression contributes to weight gain, which then contributes to sleep apnea.
- A service-connected condition prevents treatment for another medical issue, causing that issue to worsen.
In each of these situations, the second condition may qualify for benefits through secondary VA claims.
What Is “But For” Causation?
A major source of confusion involves the legal term “but for causation.”
In simple terms, “but for” causation asks whether a condition would have occurred, or become as severe, if the service-connected disability had not existed.
The concept comes from legal principles used to determine responsibility and causation. Unlike a direct cause-and-effect relationship, “but for” causation recognizes that multiple factors can contribute to a medical condition.
For example:
- A veteran develops depression that is service connected.
- The depression contributes to inactivity and unhealthy eating habits.
- Weight gain occurs.
- Sleep apnea develops.
Under a “but for” analysis, the service-connected depression may be considered part of the chain of events that ultimately led to sleep apnea.
The Spicer v. McDonough Case Explained
Much of the recent discussion stems from a 2023 court decision known as Spicer v. McDonough.
In that case, a veteran had a service-connected illness that prevented him from receiving surgery for a separate knee condition. Although the knee condition itself was not caused by military service, the service-connected illness prevented treatment that could have improved the knee problem.
The court concluded that the service-connected disability played a critical role in the worsening of the knee condition. As a result, the veteran was entitled to benefits.
The decision clarified that VA should apply a “but for” causation standard when evaluating secondary service connection.
Why Veterans Became Concerned
When the VA updated its M21 adjudication manual in May 2026 to reflect the court’s guidance, many veterans interpreted the change as a tightening of the rules.
This led to concerns such as:
- Secondary claims would become harder to prove.
- Veterans would need stronger medical evidence.
- Existing claim strategies would no longer work.
- Medical providers would need to completely rewrite nexus opinions.
According to legal experts, these concerns are largely based on misunderstandings of what the update actually did.
Did Secondary VA Claims Get Harder?
No, Secondary VA Claims Did Not Become Harder
The clarification is not considered a new law or a higher standard of proof.
Instead, it is intended to explain how VA should evaluate causation when reviewing secondary VA claims.
Importantly:
- The standard of proof remains unchanged.
- Veterans still need evidence showing a connection between conditions.
- Medical opinions should still use the “at least as likely as not” standard.
- Service-connected conditions can still support claims involving downstream medical consequences.
In theory, the clarified standard may actually make some secondary VA claims easier to establish because it recognizes broader chains of causation.
Multiple Contributing Factors Matter
Many medical conditions have more than one contributing cause.
For example, a veteran’s:
- Hypertension
- Depression
- Medication side effects
- Physical limitations
may all contribute to another health condition.
Under the clarified approach, VA should not focus solely on identifying one primary cause. Instead, adjudicators should consider whether a service-connected condition played a meaningful role in the development or worsening of another disability.
This is particularly important for veterans whose conditions developed through a series of interconnected health issues rather than a single direct cause.
Do Medical Nexus Letters Need to Change?
Most experts do not believe drastic changes are necessary.
Medical professionals should continue to:
- Review the veteran’s medical history.
- Explain the relationship between conditions.
- Use the “at least as likely as not” standard when appropriate.
- Clearly describe how one condition contributed to another.
Some providers may choose to reference “but for” causation directly, but it is not generally viewed as a requirement for every medical opinion.
Common Misconceptions About Secondary VA Claims
Several misconceptions continue to circulate online.
Misconception #1: VA Raised the Burden of Proof
The burden of proof remains the same. Veterans still need evidence showing that a connection is at least as likely as not.
Misconception #2: Secondary Conditions Must Be Directly Caused by Service
A secondary condition does not need to originate during military service. It only needs to be linked to an existing service-connected disability.
Misconception #3: Only Direct Physical Injuries Qualify
Mental health conditions, medication side effects, mobility issues, and treatment limitations can all play a role in establishing secondary VA claims.
Misconception #4: The Clarification Eliminates Existing Claims
The clarification was intended to explain how causation works. It was not designed to eliminate benefits or remove legitimate avenues for secondary service connection.
Why Understanding Secondary Conditions Is Important
Many veterans focus only on the original injury or illness that was directly connected to service.
However, service-connected disabilities often create additional medical problems over time.
Examples include:
- Knee injuries leading to hip or back conditions.
- Depression contributing to obesity and sleep apnea.
- Medication side effects causing new health complications.
- Service-connected illnesses preventing treatment for other conditions.
Recognizing these connections can help veterans identify benefits they may be entitled to receive.
Final Thoughts
The recent attention surrounding “but for” causation has caused understandable concern among veterans. However, the clarification reflected in VA guidance does not appear to raise the legal standard for secondary VA claims.
Instead, it reinforces the idea that service-connected disabilities can create chains of medical consequences that extend far beyond the original condition. When properly applied, the clarified standard may actually support veterans by recognizing a wider range of secondary connections.
Veterans pursuing secondary VA claims should continue to focus on obtaining strong medical evidence, detailed nexus opinions, and documentation that clearly explains how their service-connected condition contributed to another disability.
Also read: The Truth About Secondary Conditions and Toxic Exposure
At Prestige Veteran Medical Consulting, a veteran-owned company, we specialize in Independent Medical Opinions (IMOs) known as Nexus letters.
Our purpose is to empower YOU, the veteran, to take charge of your medical evidence and provide you with valuable educational tools and research to guide you on your journey.
Understanding the unique challenges veterans face, our commitment lies in delivering exceptional service and support.
Leveraging an extensive network of licensed independent medical professionals, all well-versed in the medical professional aspects of the VA claims process, we review the necessary medical evidence to incorporate in our reports related to your VA Disability Claim.
Prestige Veteran Medical Consulting is not a law firm, accredited claims agent, or affiliated with the Veterans Administration or Veterans Services Organizations. However, we are happy to discuss your case with your accredited VA legal professional.
