Mostly just articles as I said, not a lot of concrete numbers. Here's one side of the story: http://content.time.com/time/health/article/0,8599,1893946,00.html

Mostly just articles as I said, not a lot of concrete numbers. Here's one side of the story: http://content.time.com/time/health/article/0,8599,1893946,00.html http://content.time.com/time/health/article/0,8599,1893946,0... Compared to the European Union and the U.S., Portugal's drug use numbers are impressive. Following decriminalization, Portugal had the lowest rate of lifetime marijuana use in people over 15 in the E.U.: 10%. The most comparable figure in America is in people over 12: 39.8%. Proportionally, more Americans have used cocaine than Portuguese have used marijuana. And http://norml.org/aboutmarijuana/item/marijuana-decriminalization-its-impact-on-use-2 http://norml.org/aboutmarijuana/item/marijuana-decriminaliza... has a whole (obviously cherry-picked) list of studies supporting the claim, though most links are dead. "It has been demonstrated that the more or less free sale of [marijuana] for personal use in the Netherlands has not given rise to levels of use significantly higher than in countries which pursue a highly repressive policy." etc.