I've read several of Malcolm Gladwell's books. In "Blink" he seems to assert our first impressions are usually the correct ones. In "Outliers" he demonstrates to truly master anything in life requires a minimum of ten thousand hours of practice.
In this article he wrote for The New Yorker, he explores why there have been so many school shootings in recent years. And NO! He doesn't blame guns.
If you want to get deeper, click on the link and read it yourself. He draws a correlation between the mentality of school shooters and the mentality of a riot mob. We all have thresholds of violence. The first to throw stones in a riot usually have a threshold of 0. Those that wait and throw the stones when others are have a threshold of 2 or 3 and so on until the mob is stealing BMWs and running them into the flooded streets of New Orleans; as was the case after Katrina.
His analysis articulates school shootings as a riot in very slow motion. And, what is more terrifying, the shooters are less and less like psychopaths, and more and more like normal people behaving as members of a riot.
His theory does not explore the effects of social media nor a correlation between the shooters and medication, ADHD, or the autism spectrum; but if it is correct it proves once again we are dealing with a psychological problem and not a gun or law problem.