I know the Army can and does pull from VA records. I had a flight candidate whose physical was rejected because they knew she visited the VA a couple of times post deployment for mental health counseling.
Did this girl have PTSD? No. Did she tell the Army about the VA visits? No. Are your health records at the VA supposed to be protected by HIPPA? Yes. Was the Army allowed to look at her VA medical records? YES.
I researched this issue with the VA folks. They claim no one can see you records but then they told me about people being rejected on firearm applications because they had visited a mental health professional in the previous 2 years. Guess where the ATF got that information? Yep, VA medical records.