It looks like the government of the people and for the people might not have been lying to the people. At least not in 1936 when they were preaching against wacky tabaky. Science is now proving that people that smoke dope tend to go crazy more often than those who do not. Pretty strong evidence that you should stay away from weed if you want to stay sane.
If you can stay un-stoned all weekend a good book to check out on the subject is Reefer Madness: A History of Marijuana.
Of course you could always spend an hour watch this classic.