> It's much more accurate to describe the perpetrators as cold, empty, detached.
The article states that, according to the Secret Service, 78% of these school shooters are NOT cold, empty, detached (which would describe socio/psychopaths). Instead, they are severely depressed individuals.
If you haven't ever been severely depressed (I have) it's probably quite difficult to understand, but these are people whose minds are completely, utterly, passionately and absolutely wound up inside, anxious and stressed about perceived incurable flaws in their character and the apparently unresolvable frustration, despair, resentment and anger those beliefs generate towards themselves - and in these very sad cases, towards others.
On the outside they can appear completely normal and even happy (I went to great lengths to hide my inner turmoil during my depression); don't mistake that for what is going on on the inside. "Depression", sadly, is a dirty word in society.
Unfortunately this feeds into and reinforces the exact set of dysfunctional beliefs that drive the severely depressed individual towards, and sometimes over, the edge. Imagine feeling like a broken human, only to have society reinforce that depression means you're broken; it creates a secondary, even more powerful disturbance in your mind. This causes the depressed to withdraw even further, which is even worse for a depressed individual (notice how all of these people withdraw from normal activities before the shootings), and pretty much guarantees a horrible end.