These findings taken together raise the possibility that changing policies in Colorado, which were associated with increases in medical marijuana licensure in 2009 (see Supplemental Figure 24), may have impacted perceived harmfulness of marijuana use. Also, it is possible that medical marijuana dispensary advertising and advocacy by groups that profess the relative safety of marijuana over alcohol may have had a measurable impact. Although direct evidence of a link to perceived-risk is lacking, between 2006-2011 SAFER tax returns listed program service expenses of more than $240,000 to support public speaking, event booths and conferences to educate the public about the harms of alcohol and the “safer”, but illegal, drug marijuana (ProPublica, 2014). While marijuana legalization advocates may applaud this change in perceived harmfulness as appropriate, others may see concern that such changes will lead to worsening of marijuana use problems in Colorado.
