It's also a diversion from what all of this homicidal maniacs have in common. From the little information that trickles to us online, it seems that they've all been prescribed mind-altering pharmaceuticals, which might explain the dead look in their eyes and their blurring of fantasy and reality.
It’s not just mind altering drugs, a popular sleep aid Lunesta causes EXTREME RAGE KILLING and can from the first pill, the effects last at least 2 days. I don’t sleep well because of pain and was prescribed it. Thus speaks a single experience with it. I hid in the house for 2 days until the effects wore off, as I knew I was not my normal mellow self.
http://www.peoplespharmacy.com/2011/07/18/drugs-that-trigger-violent-behavior/