In areas with strict gun control but access to a black market, mass killings still happen with firearms (see the November 2015 attacks in Paris or the 2017 Quebec City Mosque Attacks).<p>In areas with strict gun control but limited access to firearms, mass killings still happen with other modalities. A lot of things can effectively kill a bunch of human beings assembled in a restricted area: knives, machetes, bombs, trucks, etc..<p>The idea that restricting one modality of mass killing will prevent all mass killings is misguided. Would it reduce the frequency or the lethality ? That's debatable. Someone who has decided to pursue mass killing as systematically as the Las Vegas shooter will simply find another weapon to kill en masse.
Psychiatrists can't, because nothing can.<p>People don't want to internalize the reality that society relies on an overwhelming amount of trust and there will always be abuses of trust. There are thousands and thousands of systems to prevent abuses of trust, and establish trustworthy institutions in society, but they all come at a cost, and are all fallible.<p><a href="https://www.amazon.com/Liars-Outliers-Enabling-Society-Thrive/dp/1118143302" rel="nofollow">https://www.amazon.com/Liars-Outliers-Enabling-Society-Thriv...</a>
The only way to stop mass killers is to ban and confiscate guns from the public.<p>The public should not be allowed to defend themselves with firearms. Only the government should have the monopoly on violence in a proper, respectable advanced society.
Arguably though, if we invested in way better mental healthcare for all, we might save lives / improve the quality of life for enough individuals to offset the cost off mass shootings. That being said, I think we need to restrict access to guns in general. If the government wanted to take you out, an AR15 is not going to save you from a predator drone or whatever we have in our arsenal.