What it is
If you're already service-connected for one condition, and that condition caused or made another condition worse, the new condition is also service-connected under 38 CFR § 3.310. You don't need to prove the second condition started in service, you need to prove only that the first condition caused it.
Common secondary conditions
- Sleep apnea secondary to PTSD. Documented link via weight gain, medication side effects, and disrupted sleep architecture.
- Depression / anxiety secondary to chronic pain. Living with constant pain has a documented mental-health impact.
- GERD secondary to PTSD or its medications. SSRIs and chronic stress both contribute.
- Hypertension secondary to PTSD. Recognized link via chronic sympathetic nervous system activation.
- Erectile dysfunction secondary to PTSD or SSRIs. Common, often missed. Can qualify for SMC-K ($139.87 a month in 2026).
- Radiculopathy secondary to back conditions. Pinched nerve from a service-connected back issue.
- Migraines secondary to TBI. Direct neurological causation.
- Foot conditions secondary to knee or back conditions. Altered gait causes downstream wear.
What you need to file
- Establish the primary, already service-connected and rated.
- Diagnosis of the secondary, current medical record or VA exam noting the new condition.
- Medical nexus opinion linking the secondary to the primary. A private doctor's opinion letter is the usual way to show this link.
How to file
- File a new claim on VA Form 21-526EZ, marking it as a secondary condition.
- In the contention, write it explicitly: "Sleep apnea, secondary to service-connected PTSD."
- Attach your nexus letter and any treatment records connecting the two.
Aggravation also counts
If your service-connected condition didn't cause the new condition but made it worse, you can claim the aggravated portion. The VA establishes your "baseline" before the service-connected condition came into play and rates only the additional disability beyond that baseline.