In the case of the U.S. the most one can do is admit that there is an actual serious problem and see how to go about addressing it. For that one would need better mental health care and some good measure of gun control in the country with the most guns per capita on the planet (with Yemen a far, far second). Those measure will not stop the madness from happening in plenty of instances, but they would seriously put a dent on the damage done on a civillian population in the long run.
For a curious argument about gun control, fast forward to 1:37 of the video, or watch the entirety of it to see how Bill O'Reilly goes full schizoid, tearing into gun control and then making an argument for gun control--as in: the government taking actual measures when it comes to how guns should be handled--that does make actual good sense, for full hilarious effect.
But, sadly, given that the U.S. is chock full of all kinds of monetary interests like healthcare HMOs and gun manufacturers that pay for lobbyists and politicians this is not likely to even come close to becoming a reality any time soon. Now, add to that the extremely noisy, but nevertheless quite widespread, stupid perception that Americans are a bunch of inept morons intellectually incapable of ever being able to get past those issues or being even capable of enacting efficient reforms, you are likely to be dealing with a very rarefied place to have a serious discourse about these things--all the while, someone is making a good, comfortable buck.
People will just have to deal with this.