The smirking Anders Breivik, who stunned Norway with mass murders, was taking large quantities of mind-altering chemicals.

Breivik was high on stanozolol, an anabolic steroid, and with an amphetamine-like drug called ephedrine, plus caffeine to make the mixture really fizz.

So had Michael McDermott, culprit of the 2000 Wakefield massacre in Massachusetts, Kip Kinkel, responsible for a 1998 murder spree in Oregon, John Hinckley, who tried to murder President Ronald Reagan in 1981.