Not sure where to start so I'll just dive right into the middle. It's usually deepest there and maybe I can avoid a head injury.
I have a fair amount of experience with both "mental health" and firearms. I use quotes with "mental health because I believe that it has become such a broad brush that it is largely useless as anything other than a straw man, much like "gun control". There is a very large book, now in it's 5th edition, that I use occasionally in my profession. Nearly everyone (if not everyone) that I know personally and professionally could be given a diagnosis with that book that falls under the purview or "mental illness" or "mental health".
I can't begin to count the number of people that I know and have met that own one or more firearms. I can count on one hand the number of those people that have shot at another human being outside the commission of their sworn duty to protect others. Out of those, I can count with one finger the number that have shot at another unjustifiably and with malicious intent.
I can't begin to count the number of people that I know that are on one or more psychoactive medication. Lots of those folks on meds could probably do alright with some coping skills and good counseling.The meds are a worksaver, a shortcut. I don't need a wheelbarrow to move a pile of bricks but it's a lot easier that way. A lot of other folks that I know on meds function in society because modern chemistry makes that possible. From both those groups I know a number of people that have had "adverse reactions" to their meds. Most of those were caught quickly and dealt with by changing meds or dosage. I personally don't know anyone who has tried to kill or hurt someone because they were on meds or recently coming off of them, but I do know folks who became delusional and violent because they were off of their meds long enough to decompensate that far.
I will absolutely acknowledge (and personally believe) that psychopharmacology is more akin to alchemy than science, but at this point it seems
to work for more people than it harms. I think the link above to John Ringo's facebook post is important. He is absolutely right in pointing out the potential for harm. Pharmaceutical companies and the docs that prescribe these meds need to be better educated about these risks and more open with patients and their families about monitoring changes to emotion and personality. Lots of these meds do things that nobody really understands and they affect some people in pretty bizarre ways sometimes. But, millions of people on psychoactive medications went about their daily lives today, many of them much better off, without killing anyone. Likewise, millions of gun owners, many of whom own bump fire stocks, went about their daily lives today without killing anyone. I know far more people that kept their jobs, didn't get suspended from school or arrested today in part because they are one the right combination of meds, than I know that needed a gun. I don't think it's okay to eliminate access to either because some people are assholes.
A few other thoughts. I think it is a mistake to completely separate religious, political and crazy. It would be more helpful to look at those as sort of a Venn diagram. One can be a religious zealot and cuckoo for cocoa puffs at the same time. Likewise, given the right circumstances, one wouldn't have to be Travis Bickle to get too wound up in support of a political ideology.
As far as the links between drug and alcohol abuse and domestic assault, child abuse etc. Man that's another whole thread in and of itself. I'll just sum up my thoughts by saying that sometimes the symptoms become the cause and it gets really difficult to sort things out after that.
ETA: This article showed up in my facebook feed after I posted my above rant. Much like Ringo's post, I have a few nits to pick, but it's good meat nonetheless. When something goes wrong I think that there are generally several contributing factors rather than a single cause. https://byrslf.co/thoughts-on-the-vegas ... af397cee2c