States that legalized medical marijuana had higher rates of marijuana use. Future research needs to examine whether the association is causal, or is due to an underlying common cause, such as community norms supportive of the legalization of medical marijuana and of marijuana use.
Links
[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3251168/
[2] http://rethinkpot.org/tags/legalization
[3] http://rethinkpot.org/tags/youth
[4] http://rethinkpot.org/tags/study
[5] http://rethinkpot.org/tags/research