Slow Your Roll, Dr. Humphreys. It’s too early to enact a cap on the THC content of legal cannabis

By Debbie Shipman

An open letter in response to a Washington Post editorial calling for states to regulate cannabis potency.

Dear Dr. Humphreys, 

It is premature to propose legislation based on a single newly-published study. Ideally, we make laws to solve existing problems, not hypothetical dangers with little evidence to conclude a that there is a potential problem. 

Screenshot from Washington Post online.

While you assert in your first paragraph of Why States Should Limit the Potency of Marijuana that the study in question “suggests… {high potency cannabis} could create public health problems down the road as more users become addicted or otherwise impaired,” the authors of the article draw no such conclusions. They do say, “it is essential that policy makers consider the effects of new legislation on cannabis potency and the incidence of cannabis-related harms.”  The nuance between your conclusions and their statement is that the authors are suggesting that policy makers should keep an eye on the topic while you are ready for staff aides to begin penning legislation. Furthermore, you have more confidence than even they claim in their conclusions of the study. “If cannabis potency does contribute to drug treatment admissions (which cannot be established on the basis of this single observational study), our finding that the strongest association occurred at 5 years (extending to 7 years in fully adjusted models) suggests that this effect occurs at a mid-early stage in cannabis use trajectories.” Words in parenthesis copied from the original text. In other words, this study is a starting point to look at correlations between delta-9-tetrahydrocannabinol (THC) and cannabis use disorders. It also suggests to me that researchers might be interested in further study of both the correlation between age of first use and cannabis use disorders, and also the effects of increasing potency on long-term users, including any differences on the quantity of cannabis consumed when users choose high THC cannabis over less potent strains.

In the coming days the study author's peers will review this study. They will search for weaknesses in the study design and debate the study’s contribution to science. Until that happens, here are a few issues I have with the study and your conclusions about what it means in relation to regulating the THC content of cannabis.

The study’s authors claim as a strength of their study its research population, residents of the Netherlands who were treated for cannabis use disorder. “Official tolerance of cannabis use in the Netherlands minimises confounding influences of the criminal justice system and/or stigma.” On the contrary, I find the research population weak in terms of what conclusions we can draw about U.S. cannabis users, who live under much harsher, though currently relaxing, drug laws. Drug users seek drug treatment for numerous reasons; some come to the decision to seek treatment on their own, but the majority are coerced by family members, lawyers and the criminal justice system. At least that is how it works in the United States.

In the Netherlands, “Drug use as such does not constitute a crime in legal terms… the possession of small quantities of drugs for personal use is not subject to targeted investigation by the police…Drug users are convicted when they have committed a crime such as selling drugs, theft or burglary. A special law — the Placement in an Institution for Prolific Offenders — was introduced in 2004 for the treatment of persistent offenders, of which problematic drug users constitute a major proportion. The measure consists of a combination of imprisonment and behavioural (sic) interventions and treatment, which are mostly carried out in care institutions outside prison.” What this means is that the Dutch focus on catching and helping abusers without sweeping simple drug users and other offenders up into their net, like the U.S. currently does. Plus, with universal healthcare, true addicts, no matter their income level, have ample access to inpatient and outpatient treatment. The cost of addiction treatment in the U.S. rivals the annual pay of a significant number Americans, and if they have insurance at all, it usually pays only for inpatient treatment one time. 

Screenshot from High Times

While it is true in the U.S. that most people charged with simple possession of marijuana are not prosecuted, much less sentenced to prison, the same cannot be said for those sent to drug treatment programs. While the Netherlands sends to mandatory treatment cannabis users who make themselves a persistent public nuisance, in this country we often send people to treatment for crimes only tangentially tied to drug use. For example, a teen caught in possession of marijuana while shoplifting makeup could be coerced into a drug treatment program by the court, or by a parent or lawyer as a move to avoid prosecution. Never mind that the kid started shoplifting at age 12 and didn’t smoke pot until 17, and that a tube of mascara won’t go far in a drug trade.

For those in urgent need, there is also the problem that drug treatment can be difficult to access in the U.S., either voluntarily or mandatorily. Most states have long waiting lists for drug treatment programs and the window of opportunity that an addict has to voluntarily self-commit to treatment often slams shut before a bed becomes available. It is reasonable to conclude, therefore, that a higher percentage of Dutch cannabis users than American users get treatment for actual, and not presumed, problem use of the plant. In short, this study from the Netherlands relies on data captured from people who experience cannabis within a very different healthcare and legal environment than their American counterparts.

Another issue I have with the study design is the method of determining the THC content of the cannabis that users in treatment had available over the study time period. They purchased the samples legally from coffee shops, which I doubt is representative of the cannabis most cannabis users who live in country consume. The study’s authors argue that their method is “advantageous to other studies utilising (sic) cannabis samples from police seizures, which may be biased by law enforcement methods.” While it is true that the majority of cannabis that is purchased in legal dispensaries has higher THC content than that available in the past, it is also true that significant numbers of cannabis users who can legally use cannabis get their product from non-commercial sources. I live in Colorado and have many friends and acquaintances who use cannabis they grow themselves, or they get it from friends who grow. Sure, a lot of casual users and people who love to experiment with different strains for medical or recreational purposes buy professionally grown cannabis, as do tourists. Hobby growers, however, produce a significant amount of the cannabis consumed in Colorado, as I'm sure is the case in other places where consuming cannabis is not illegal. This is not to say that hobby growers don’t produce high THC content product, but I doubt it is consistently as potent as that of professional horticulturists who supply legal dispensaries. Law enforcement-seized cannabis samples may be problematic, however excluding the cannabis actually found in the possession of users, I believe, skews the data.

One thing you need to understand about cannabis potency is that not all users are seeking the same effect, and not all users seek the same effect every time they use. Users whose goal is to get stoned are likely to choose high THC strains while users who seek relief from auto-inflammatory diseases or seizure disorders are likely to choose high CBD/low THC strains. CBD decreases the effects of THC. Someone suffering from cancer pain might obtain relief only from a high potency strain, but that same cannabis sample may cause severe anxiety in another user, which would deter use of that strain in the future. Just because higher THC strains are available does not mean that all consumers will choose them over less potent strains, especially if a higher CBD product resolves the symptoms they are medicating. Not one of the top ten highest THC strains in 2017 were among Leafly’s top ten most popular strains sold that year, which jeopardizes arguments about the dangers of higher THC content as well as the addictiveness of the plant altogether. (Cannabis may actually be effective in treating opioid and other addictions)

Any laws we enact regarding legal cannabis should take into account how cannabis is actually used by the majority of users, as opposed to how cannabis could potentially be misused in the future. Furthermore, we must always look at unintended consequences of proposed laws and refrain from acting in haste to codify laws out of an overabundance of caution. The cure may be worse than the disease. In your call for regulation, you say, “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 service.” 

You claim there is a regulatory gap, but I see no evidence of a gap. Slow your roll, Dr. Humphreys. Regulation of cannabis potency is a solution in search of a problem. 

Debbie Shipman has a BA in English/Technical Writing and an MA in Political Science, both from Oklahoma State University. She enjoys writing on public policy, criminal justice, cannabis prohibition and whatever else pops into her head.