Lessons learned after three years of legalized, recreational marijuana: The Colorado experience.

In November 2012 Colorado voters approved legalized recreational marijuana. On January 1, 2014 Colorado became the first state to allow legal sales of non-medical marijuana for adults over the age of 21. Since that time, the state has been monitoring potential impacts on population health. In this paper we present lessons learned in the first three years following legal sales of recreational marijuana. These lessons pertain to health behaviors and health outcomes, as well as to health policy issues. Our intent is to share these lessons with other states as they face the prospect of recreational marijuana legalization.