In looking at the data for pot usage in CO around legalization, the data is mixed. Teen usage rates of pot went down after legalization, while adult usage rates went up. The 2020 data is not yet out from what I could see. Like with all drugs, potentiation will alter the dosage rates of individuals, so data on weight of drug sold needs to be calibrated over time. Though pot and heroin are vastly different drugs in terms of effect and addiction, the pot legalization effects provide some guidance on usage among those that can purchase it legally. Per what little data I could see, it does seems that legalization increases use of the drug. As to what that does towards safety and health, I've no clue and would love it if another HNer could enlighten us.

https://www.google.com/search?q=chart+marijuana+usage+in+col...