Early data from Colorado suggest teenage use of marijuana is down since legalization

I have tended to assume that teenage use of marijuana would likely increase in the wake of legalization in Colorado, but the early data suggest a reduction in teenager use of marijuana since the stuff became legal for adults.  This recent news report, headlined "Pot Use Among Colorado Teens Appears to Drop After Legalization," provides these details:

Marijuana use among Colorado high school students appears to be declining, despite the state’s pioneering voter-approved experiment with legalization. According to preliminary data from the state’s biennial Healthy Kids Colorado Survey, in 2013 - the first full year the drug was legal for adults 21 and older - 20 percent of high school students admitted using pot in the preceding month and 37 percent said they had at some point in their lives.

The survey’s 2011 edition found 22 percent of high school students used the drug in the past month and 39 percent had ever sampled it. It’s unclear if the year-to-year decline represents a statistically significant change, but data from 2009 suggests a multiyear downward trend. That year 25 percent of high school kids said they used pot in the past month and 45 percent said they had ever done so.

The data released Thursday by the Colorado Department of Public Health and Environment also appears to show post-legalization pot use among Colorado teens was lower than the national average....

Supporters of marijuana legalization argue underage use will shrink as states impose strict age limits. Opponents of legalization, meanwhile, fear that declining perceptions of harm associated with the drug will lead to an uptick in teen use. According to the data released Thursday, students surveyed do have a lowered perception of harm - 54 percent perceived a moderate or great risk in using the drug, down from 58 percent in 2011 - but use did not increase.

“Once again, claims that regulating marijuana would leave Colorado in ruins have proven to be unfounded,” Marijuana Policy Project Communication Director Mason Tvert said in a statement. “How many times do marijuana prohibition supporters need to be proven wrong before they stop declaring our marijuana laws are increasing teen use?”

Tvert, co-director of Colorado’s successful Amendment 64 legalization campaign, said “the drop in teen use reflects the fact that state and local authorities have far more control over marijuana than ever before.” He argues “our goal should not be increasing teens’ perception of risk surrounding marijuana. It should be increasing teens’ knowledge of the actual relative harms of marijuana, alcohol, and other substances so that they can make smart decisions."

Foes of legalization haven't thrown in the towel. "No statistician would interpret that as being a decline," Kevin Sabet, co-founder of the anti-legalization group Smart Approaches to Marijuana, says of the 2 percentage point year-to-year drop. Sabet says it will be important to review county-level data when full survey results are released later this year and points out that state-licensed stores were not open in 2013.