It can also decrease the use of dangerous legal medication, and the use of alcohol.making pot legal will only increase more kids using it. That's all we need: more dumb kids walking around with their pants just above their knees.
The study above concerns minorities of heavy pot consumption, you should compare with heavy alcohol consumption.
Illegality of marijuana is just a nonsense. Prohibition of drugs too, it can only lead to organized drug state dealing.
How the land of the free can be worst than North Korean communism in the domain of health remains a sort of mystery for me.