The Dutch findings are relevant to the United States because high THC marijuana products have proliferated in the wake of legalization. The average potency of legal marijuana products sold in the state of Washington, for example, is 20 percent THC, with some products being significantly higher.
Although some people believe prohibiting drugs is what makes their potency increase, the potency of marijuana under legalization has disproved that idea. Potency rises in both legal and illegal markets for the simple reason that it conveys advantages to sellers. More potent drugs have more potential to addict customers, thereby turning them into reliable profit centers.
In other legal drug markets, regulators constrain potency. Legal alcohol beverage concentrations are regulated in a variety of ways, including through different levels of tax for products of different strengths as well as constraints on labeling and place of sale. In most states, for a beverage to be marketed and sold as “beer,” its alcohol content must fall within a specified range. Similarly, if wine is distilled to the point that its alcohol content rises too high, some states require it be sold as spirits (i.e., as “brandy”) and limit its sale locations.
As states have legalized marijuana, they have put no comparable potency restrictions in place, for example capping THC content or levying higher taxes on more potent marijuana strains. Sellers are doing the economic rational thing in response: ramping up potency.
The Dutch results suggest users and the public will suffer from this regulatory gap as more consumers of high-strength marijuana will fall victim to significant ill effects. However, this is an avoidable problem. Government can and should place limits on marijuana’s strength just as it does other addictive products, thereby protecting public health as well as saving the taxpayer the future costs of treatment and other needed health-care services.