Difference between PTSD and major depressive disorder

The primary difference between PTSD and major depressive disorder (MDD) for VA rating purposes is the required nexus (connection) to service: PTSD requires a diagnosis linked to a specific in-service stressor (a credible fear of hostile military or terrorist activity, per 38 CFR 3.304(f)), while MDD can be service-connected based on aggravation of a pre-existing condition, as in your case, per 38 CFR 3.306. Both are rated under the General Rating Formula for Mental Disorders (38 CFR 4.130, using Diagnostic Codes 9201-9440), meaning they are evaluated based on identical occupational and social impairment criteria—your 70% rating reflects the severity of symptoms, not the diagnosis. However, a key legal distinction is that you cannot receive separate ratings for PTSD and MDD if they share overlapping symptoms; they must be combined under one rating per *Esteban v. Brown*. Your decision’s wording is crucial: it establishes an aggravation nexus, which is generally permanent, but you should carefully review your file to ensure the VA properly applied the "aggravation beyond natural progression" standard from *Allen v. Brown*. Actionable next steps: 1) Obtain your C-file to review the examination that concluded your MDD was pre-existing but aggravated; 2) If you have symptoms specifically tied to an in-service traumatic event (e.g., nightmares, flashbacks, avoidance), consider seeking a diagnosis for PTSD, as a direct service connection (rather than aggravation) may offer stronger protection against future reduction if your MDD symptoms improve; and 3) For any increase claim, focus on documenting worsened symptom severity per the criteria in 38 CFR 4.130, not just the diagnosis. **This is for educational purposes only and not legal or medical advice.**