You want "studies"? I´ll give you "studies", for what it´s worth:

http://www.equalrights4all.org/potpr...ppingstone.htm

"To cite just one example, the Partnership for a Drug Free America, an influential media-based interest group, includes marijuana with other drugs in its advertisements, communicating the message that marijuana in fact is a "gateway" to more dangerous drugs.' "

"Swedish drug policy is based on the assumption that people trying and using cannabis during their school years constitute a recruiting base for those who later become heavy drug abusers."

http://www.mapinc.org/drugnews/v97.n196.a04.html

And this i found in a quick search! Imagine if i had more time...
Scientists can never agree to anything, and they usually fall under a more political pressure to produce certain results.
If you want to really know the problem, you need to be a part of it, and you need to experience it hand to hand, on the streets. Not on some office surrounded of guys in white coats.
:indeed:

Some more links:
HERE:

__________________
"Quincitilius Varus, give me back my legions!"
Emperor Augustus of Rome.