So then denying someone the right to buy a gun, based on being a vet with PTSD, would accomplish what? If they already have guns as you stated. You're practically making my point for me...
If someone had an episode of depression twenty years ago, was treated with meds and declared ok after six months, would you deny them 2A rights still?
How will you get all this info? Will we have a database with everyone's psyche profile up in Washington DC?
Who will judge who is sane enough to exercise a Constitutional right? Their own shrink? A panel of Government-employed shrinks? Slippery slope anyone?
The point I'm trying to make is this is a more complex issue than some want to paint it, and that there are implications and unintended consequences galore for going very far down this path.
As I said though, I'm all for adding "involuntarily committed" as a red flag on NICS. I don't think it will help very much at all, but since it would be minimally intrusive to 2A rights I'd be okay with it.