Check out the source article. It looks like when Colorado legalized marijuana the rate of teen (12-17yrs) use of marijuana in 2015 and 2016 has dropped to the lowest level seen in almost a year as reported in this federal survey.
And that’s not all, heroin, alcohol and tobacco use are also way down as well.
Colorado Considers End Run if Feds Crack Down on Recreational Marijuana
The Trump Administration has said it will view medical marijuana leniently but is considered renewed federal enforcement to shut down recreational marijuana sales legal in eight states and the District of Columbia. Lawmakers in Colorado have proposed a simple solution.