Here's my problem with your assertion: Psychological evaluation is NOT an exact science; It is based heavily upon the OPINION of the evaluator.
Further, the DSM is NOT written strictly by psychologists -- it is written by a committee, many of whom represent financial interests (such as the pharmaceutical companies making psychotropics that now "just happen" to be cures for "defined disorders" -- see how that works?) and not medical ones.
Therefore, I assert that the entire psychological discipline is rife with potential for bias and abuse, and therefore should NOT be used to gauge whether or not an individual may exercise a civil right.
And I'll let you in on a little secret -- just becuase someone has a mental disorder does NOT automatically make them crazy. Some of us are actually BETTER able to work or live in certain environments BECAUSE of what could be classified as a "mental disorder".
Take my line of work for example. The kind of things Medics deal with on a daily basis would make most "normal, well-adjusted" people lose their lunch. They react "normally" to horror and pain and death. WE DON'T. We treat it as "Business as usual."
Some folks gain this perspective by acclimation, others are just "well suited for the job."
There are those who would say there's something WRONG with us.
But, as one of my old medic instructors pointed out: "Of COURSE there's something wrong with all of us! We react ABNORMALLY to situations every single day! We HAVE to, IT'S OUR JOB! But it takes a special kind of crazy to do what we do. What's wrong with us allows to do what's right. And that's part of why we do it."
So before you go trying to make a judgment call regarding sanity, understand that it's not that simple, and having a minor disorder, or even being bat-snot nuts about something may not preclude the exercise of the civil right of arms for self defense.
What I'm saying is, be VERY careful about recommending "requirements" based upon soft sciences -- they can be abused to the point of being the very discriminatory laws that gun control was originally set up to be (to disarm recently freed slaves -- go ahead, look it up.)
So while I agree that everyone should keep and bear arms to the best of their judgment, I disagree that the government should psychologically "evaluate" those before licensure -- for personal carry.
For professional carry, it's a bit different. The liability is different. Psych evals have been in place for those who carry firearms related to work for about 35 years now. And you know what? I'm going to say I'm not particularly impressed, considering how many situations I've PERSONALLY been in where someone who has been certified "sane" goes screwy, as in, "Hi, I'm here to take you to the Crisis Center" screwy.
Because the guy doing the transporting?
That was ME.
I've seen a lot of this stuff firsthand, which is a good part of the reason why my faith in psychologists and psychiatrists is pretty much in the toilet. Because they're perfectly okay with writing a diagnosis or a scrip and then leaving me alone to take care of the patient -- because they seem to think their answer is the entire answer for a very complex human being's behavior.
And I'll tell you from personal experience - THAT AIN'T SO.
"Why is he in restraints?" "Because you misevaluated him, doctor." "That's not possible." "Oh? I'll just let him out and you can evaluate him again without me and the five security guys here." "That won't be necessary..."
Yeah. No psych evals, please.