Doubt cast on cannabis, schizophrenia link
http://www.cbc.ca/health/story/2009/09/02/cannabis-schizophrenia.html (Via flocked flist post)
Basically, they looked at periods of large cannabis usage increase in the population, and showed that there was no increase in schizophrenia cases as a result. QED, no link. Science!
(No, I don't use any illegal drugs. Important side-effects of illegal drug use include Social Opprobrium, Economic Poverty and Loss of Liberty (and possibly being raped). None of those are pharmacological reactions, however.)
ED: Then again, there are good reasons not to indulge, as well...