Citations? I hadn't seen any facts for or against either of these questions thus far (At least in the United States).Will drug use rise after legalization? Yes, but not very much. After legalizing pot there was hardly any increase in pot smokers. But a lot less drug related crime.
I couldn't find any english citations because most of this research is dutch. But here's the wikipedia entry on our drug policy: http://en.wikipedia.org/wiki/Drug_policy_of_the_Netherlands Late new developments enforced by a right wing government have backfired.
I was mostly curious with regards to the US. Drug culture is highly variable across countries and continents. Extremely strict gun and drug laws have been successful at reducing crime and addiction in small Asian countries like Korea and Japan, but that approach hasn't shown much promise in the US. I'm aware of Portugal's example, too, but your comment made me curious if there had been further studies within the US with regards to recent laws decriminalizing / legalizing cannabis in various states.