The burden of proof isn't in proving you don't have PTSD, you've got that backwards.
And its go nothing to do with being liberal, you people just don't want to do anything about the gun problem. You don't care. Even when you say guns aren't the problem, crazy people are the problem, you still won't do anything about the crazy people.
The only "gun problem" is that not enough good people have guns.
Actually the term PTSD originated in 1980 and though it was called "shell shock" at the time has been a fairly widely recognized serious issue since WWI. It's been a legitimate concern for almost 100 years; most doctors just didn't know how to treat it or address it in the past. And sadly a lot of the methods we use today to treat PTSD come from W.H. Rivers, a doctor during WWI who pretty much paved the way for anything concerning PTSD. The fact that we're still using 100 year old methods doesn't help...
People with PTSD certainly aren't all crazy, but it's not like we're just now starting to think it can be something serious; we've known for a while. I'm sure you could look at any soldier, cop, firefighter, even most doctors, and find PTSD symptoms if you wanted to, and that's the issue here... Most people with any sort of PTSD symptoms are absolutely normal; only a tiny fraction come unhinged.