As public opinion increasingly turns in favor of marijuana legalization–and medical marijuana legalization in particular–the last line of defense for pot prohibitions remains, “But think of the children!”
Except, according to a new study from Columbia University researchers, legalizing medical marijuana has no discernible effect on teen drug use.
The study, published in The Lancet Psychiatry, reviewed marijuana use by over a million teenagers from 48 states, spanning 24 years—1991-2014.
The researchers determined that, “The risk of marijuana use in states before passing medical marijuana laws did not differ significantly from the risk after medical marijuana laws were passed.”
“[T]he results of this study showed no evidence for an increase in adolescent marijuana use after passage of state laws permitting use of marijuana for medical purposes,” they write, concluding that “concerns that increased adolescent marijuana use is an unintended effect of state medical marijuana laws seem unfounded.”
And among eighth graders, they actually discovered a decrease in marijuana use. They postulate that this may be because “10th and 12th graders had already formed attitudes towards marijuana and hence were not influenced by medical marijuana laws, but the younger 8th graders had more modifiable attitudes and beliefs about marijuana, and were less likely to view marijuana as recreational after states authorised its use for medical purposes. “
They did find more overall drug use in states that had legalized medical marijuana, but believe this to be the result of “state-level risk factors other than medical marijuana laws.” They encourage states to investigate these “societal” factors if they hope to impact teen drug use.
At Forbes, Debra Borchardt notes that this backs up previous research: