"It's the drugs, stupid. In hundreds of square miles of supposed analysis of the Norway mass murder, almost nobody has noticed that the smirking Anders Breivik was taking large quantities of mind-altering chemicals. In this case, the substances are an anabolic steroid called stanozolol, combined with an amphetamine-like drug called ephedrine, plus caffeine to make the mixture really fizz. I found these facts in Breivik’s vast, drivelling manifesto simply because I was looking for them. The authorities and most of the media are more interested in his non-existent belief in fundamentalist Christianity. I doubt if the drugs would ever have been known about if Breivik hadn’t himself revealed this."
This and more from Peter Hitchens in the Mail on Sunday, who looks at the drug-addled minds of other mass killers.