Nexus Letter

What is a "Nexus Letter?"

A nexus letter is a formal medical or mental health opinion used in U.S. Department of Veterans Affairs (VA) disability claims to establish a causal connection (“nexus”) between a veteran’s current diagnosed condition and their military service.

Purpose

The VA requires three elements to grant service connection:

1. A current diagnosis

2. An in-service event, injury, illness, or stressor

3. A medical nexus linking the two

The nexus letter addresses the third element, which is often the deciding factor in a claim.

Who Writes It

A nexus letter must be written by a qualified, licensed medical or mental health professional, such as:

• Physician (MD/DO)

• Psychologist (PhD/PsyD)

• Psychiatrist

• Licensed clinical social worker, professional counselor, or marriage and family therapist (within scope and state law)

The provider does not need to be a VA clinician.

Required Components

A strong nexus letter typically includes:

• The provider’s credentials and licensure

• Confirmation of records reviewed (e.g., service treatment records, C&P exams, medical records)

• The veteran’s current diagnosis

• A clear medical opinion using VA-specific language:

  “It is at least as likely as not (50% probability or greater) that the veteran’s condition is related to military service.”

• A clinical rationale explaining how service events led to or aggravated the condition

• Signature, date, and contact information

Common Uses

Nexus letters are frequently used for:

• PTSD and other mental health conditions

• Chronic pain, migraines, sleep apnea

• Orthopedic injuries

• Secondary service connection (e.g., depression secondary to chronic pain)

• Aggravation of pre-existing conditions

Why They Matter

VA Compensation & Pension (C&P) examiners often deny claims due to “no nexus.” A well-written nexus letter can:

• Rebut an unfavorable C&P opinion

• Strengthen an initial claim

• Support an appeal or supplemental claim