Best certification for requesting disability accommodations for GRE? I am planning to take the GRE Subject Test in Math. I have ADHD and would like to request accommodations.

I live in a first world country now but used to be based in a third world country. In this third world country I was seeing a resident psychiatrist.

I am about to have a new psychiatrist who is not a resident.

This psychiatrist has met me for only an hour while my old psychiatrist , the resident, met with me for over 12 hours already.

What certification should I submit to ETS?

new doctor only? Old doctor though resident only? Both?
Follow the instructions given by ETS. They are very specific about what kind of documentation they need.

Give your current psychiatrist the link and ask if he/she can provide everything on it, and if not, what he/she recommends you do to collect the necessary documentation.