How should policy makers regulate the tetrahydrocannabinol content of cannabis products in a legal market?

An increased use of high potency cannabis products since cannabis legalisation in the United States, Canada, and elsewhere may increase cannabis-related harm. Policy makers have good reasons for regulating more potent cannabis in ways that minimise harm, using approaches similar to those used to regulate alcohol, namely banning the sale of high potency cannabis, setting a cap on tetrahydrocannabinol (THC) content, and imposing higher rates of taxes on more potent cannabis products. Given the difficulty that US policy makers have had in regulating cannabis extracts and edibles, governments that are planning to legalise cannabis need to put policies on extracts into enabling legislation and evaluate the impact of these policies on cannabis use and cannabis-related harms.