Daily Mail's Peter Hitchens seems to be ignorant of this fact.
- ...Lee Rigby’s killers, who underwent violent personality changes in their teens after becoming cannabis users. ...The recent Paris killers were also known users of cannabis. So were the chaotic drifters who killed soldiers in Canada last year. So is the chief suspect in the Boston Marathon bombings of April 2013. ...Jared Loughner, who killed six people and severely injured Congresswoman Gabrielle Giffords in Arizona in 2011, was also a confirmed heavy cannabis user... the pointless killing of Sheffield church organist Alan Greaves, randomly beaten to death by two laughing youths on Christmas Eve 2012. Both were cannabis smokers. ...the link is interesting. I wonder how many other violent criminals would turn out to be heavy cannabis users, if only anyone ever asked.
Mental illness is not a precursor to criminal behavior. Many criminals may suffer from one form of mental illness or another, and there may be significant correlation between the two, but little in the way of scientifically proven causation.
It's even entirely possible that Mr Hitchens has it all backwards. It might be that those inclined toward criminal activity are more likely to use drugs, including cannabis, instead of the other way around.
Furthermore, Mr Hitchens disregards other articles also released in the past week1, 2, also from the Daily Mail, that offers a supposedly scientific study which shows both alcohol and tobacco are more dangerous than cannabis.
I wonder how many of the criminals he mentioned above ingested alcohol.