Reviewed by Jonathan Teplitsky · Updated August 2026
What a PTSD nexus letter must contain to be effective
A strong PTSD nexus letter needs six things: the provider's credentials, a statement that they reviewed your records or claims file, a clear PTSD diagnosis under DSM-5 criteria, the specific in-service stressor tied to that diagnosis, a medical rationale connecting the two, and the conclusion that your PTSD is "at least as likely as not" related to that stressor. Miss any of these and the letter loses weight with a rater.
This page gives you a real, fill-in-the-blank template plus the current VA rating table. If you also need a Disability Benefits Questionnaire, see our DBQ explainer first.
What a nexus letter is, and why PTSD is usually a direct claim
A nexus letter is a doctor's written medical opinion that connects a diagnosed condition to its cause. For VA purposes that cause is either direct (something that happened in service) or secondary (another already service-connected condition).
PTSD is usually filed as a direct claim. The diagnosis itself requires a specific traumatic event, called a stressor, that ties the condition to service under DSM-5 criteria. See our full VA PTSD rating guide for the diagnosis and rating basics.
A secondary or aggravation path also exists. PTSD can worsen an existing service-connected condition, or another condition can develop because of PTSD. Sleep apnea is a common example, covered in our sleep apnea secondary to PTSD guide and our dedicated sleep apnea nexus letter template. For any other diagnosis, our general nexus letter template covers the format.
The stressor: what a nexus letter can and can't prove
PTSD claims need two separate pieces of evidence, not one. The nexus letter supplies the medical opinion, the rationale linking your diagnosed PTSD to a stressor. A second, separate step is corroborating that the stressor happened, which VA gathers largely through VA Form 21-0781.
The corroboration bar depends on the stressor type. Combat-related stressors get relaxed evidentiary treatment. If your service records confirm you served in combat, your own credible statement can be enough, with no further corroboration required, under 38 CFR 3.304(f).
Non-combat stressors generally need more support. Training accidents, non-combat threats to life, and similar events often require buddy statements, incident reports, or other records placing the event in service. Military sexual trauma claims also get relaxed evidentiary rules, since those incidents are rarely reported through official channels.
A nexus letter that skips this distinction is incomplete. The provider should name the specific stressor relied on, since VA still has to verify that the event occurred before the medical opinion can carry the claim.
The 5 elements of a strong nexus letter
- Credentials. Who the provider is, their license and specialty, and why they are qualified to diagnose and opine on PTSD.
- Records reviewed. A statement that they reviewed your service records, medical history, and/or C-file, not just a single visit.
- Diagnosis. A PTSD diagnosis meeting DSM-5 criteria (rated under Diagnostic Code 9411), including the Criterion A stressor the diagnosis is built on.
- Rationale. The medical "because": how the specific stressor produced the diagnosed symptoms. This is the heart of the letter.
- Conclusion. The "at least as likely as not" opinion stating the link between the stressor and the diagnosis.
The "at least as likely as not" standard
VA does not require certainty. Service connection only needs a probability of 50% or greater, phrased as "at least as likely as not." Because of the benefit-of-the-doubt rule in 38 CFR 3.102, when the evidence is in equipoise VA must decide in the veteran's favor. Vaguer phrases like "could be related" or "consistent with" fall below this threshold and give a rater room to deny.
Weight tip: The conclusion sentence alone is not enough. A bare "it is at least as likely as not" with no reasoning gets little probative value. The rationale tying your specific symptoms to your specific stressor is what makes the opinion persuasive to a rater or the Board.
Fill-in-the-blank nexus letter template
Copy the version that fits your claim, replace every [bracketed] placeholder, and have your provider review, complete, and sign it on their letterhead.
Direct service connection (most common for PTSD)
[Provider Name], [Credentials/License] · [Clinic / Address] · [Date]
RE: [Veteran Name], [VA File Number / SSN]
I am a [psychiatrist / psychologist / licensed clinical social worker / NP] licensed in [State], with [X] years treating trauma-related conditions. I have reviewed [Veteran]'s service treatment records, VA medical records, [VA Form 21-0781 stressor statement], and claims file (C-file).
[Veteran] is diagnosed with posttraumatic stress disorder (PTSD) meeting DSM-5 criteria, including Criterion A exposure to [describe the qualifying stressor, e.g., an in-service attack on (date/location)].
It is my professional medical opinion that [Veteran]'s PTSD is at least as likely as not (50% or greater probability) caused by the above in-service stressor.
Rationale: [Explain the mechanism, e.g., [Veteran] reports re-experiencing symptoms, hypervigilance, and avoidance behaviors that began following the stressor and have continued since. The reported symptom pattern and onset are consistent with the diagnosed stressor and the accepted course of PTSD.]
Sincerely, [Signature] · [Provider Name, Credentials]
Secondary or aggravation (PTSD worsening, or worsened by, another condition)
[Same header and credentials block as above.]
[Veteran] is service-connected for [primary condition, e.g., PTSD] at [XX]%. [Veteran] is also diagnosed with [secondary condition, e.g., sleep apnea / hypertension].
It is my professional medical opinion that [Veteran]'s [secondary condition] is at least as likely as not (50% or greater probability) caused by, or alternatively aggravated beyond its natural progression by, the service-connected PTSD.
Rationale: [Explain the mechanism, e.g., chronic hyperarousal and disrupted sleep associated with PTSD are a recognized contributor to obstructive sleep apnea, and records show the onset or worsening of (condition) following the PTSD diagnosis.]
Sincerely, [Signature] · [Provider Name, Credentials]
Who can write it
The opinion must come from a qualified medical provider. This is typically a psychiatrist, psychologist, licensed clinical social worker, or in many cases a nurse practitioner or physician assistant experienced in trauma-related conditions. It can be your treating provider or an independent provider you hire.
A lay statement you write about your own symptoms and stressor is valuable supporting evidence. It is not a medical nexus and cannot replace the provider's signed opinion.
How PTSD is rated (DC 9411)
PTSD is rated under 38 CFR 4.130, Diagnostic Code 9411, using the same General Rating Formula for Mental Disorders that applies to depression and other psychiatric conditions:
| Rating | General level of impairment |
|---|---|
| 0% | Diagnosed, but symptoms not severe enough to interfere with work or social functioning, or to require continuous medication. |
| 10% | Mild or transient symptoms; decreased efficiency only during periods of significant stress, or symptoms controlled by continuous medication. |
| 30% | Occasional decrease in work efficiency with intermittent periods of inability to perform tasks, though generally functioning satisfactorily. |
| 50% | Reduced reliability and productivity; flattened affect, panic attacks more than once a week, impaired judgment, and difficulty in social and work relationships. |
| 70% | Deficiencies in most areas, including work, school, family relations, judgment, and mood; symptoms such as suicidal ideation and near-continuous panic or depression. |
| 100% | Total occupational and social impairment; symptoms such as persistent delusions, gross impairment in communication, or persistent danger to self or others. |
Common mistakes that sink PTSD nexus letters
- Using weak language ("could be," "consistent with") instead of "at least as likely as not."
- Stating the conclusion with no rationale. The reasoning is what gives the opinion weight.
- Not naming the specific stressor the diagnosis and opinion are based on.
- Treating the nexus letter as proof the stressor happened. Corroboration is a separate step, usually built through VA Form 21-0781 and supporting records.
- No statement that the records or C-file were reviewed.
- An unsigned letter, or one signed by the veteran rather than a provider.
Important: This is an educational template, not legal or medical advice. The nexus letter must be completed, reviewed, and signed by a qualified medical provider, and stressor corroboration should be handled alongside it. For help with a denial or appeal, see whether you need a VA appeals attorney.
PTSD nexus letter, quick FAQ
Can I write my own PTSD nexus letter? You can draft the template, but a qualified provider must author and sign the actual opinion.
What's the magic phrase? "At least as likely as not," a 50% or greater probability, which triggers benefit-of-the-doubt under 38 CFR 3.102.
Is PTSD a direct or secondary claim? Usually direct, tied to an in-service stressor. It can also be filed secondary to, or as aggravating, another condition.
Does the nexus letter prove my stressor happened? No. It supplies the medical opinion. Stressor corroboration is a separate step, often through VA Form 21-0781 and supporting records, though combat stressors get relaxed evidentiary treatment.
What code is PTSD rated under? DC 9411 under 38 CFR 4.130, at 0/10/30/50/70/100%.
Does a combat stressor need corroboration? Often not. If your service records confirm combat service, your own credible statement about the stressor can be enough under 38 CFR 3.304(f).