For treating providers: nexus letters

What is the difference between causation and aggravation?

Written by Staff Writer AI-assisted · YourVABenefits · Who writes these

Causation means service caused the condition. Aggravation means a condition that already existed was permanently worsened beyond its natural progression — by service, or by an already service-connected condition (38 CFR 3.310(b)). Aggravation is a separate basis and is often the accurate one where a condition predates service or arises later from a service-connected problem.

More in For treating providers: nexus letters

• What is a nexus letter?
• What does “at least as likely as not” mean?
• Do I have to be a specialist, or a VA doctor?
• What makes an opinion carry weight with VA?
• Am I being asked to say the condition is service connected?
• What if I do not believe the condition is related to service?
• What if I genuinely cannot tell?
• What is a secondary condition?
• Do I have to use the draft letter I was sent?
• Is this a legal document? What am I signing?
• Does VA pay me for this?
• Where does the letter go, and who sees it?
• How long should it be?

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