By Joe Broadmeadow
The marijuana that fueled Woodstock in August of 1969 tested somewhere between one and three percent THC. Half a million people spent three days in a muddy field in Bethel, New York, and the weekend’s enduring hazards were a warning from the stage about the brown acid and a parking lot nobody could find.
Run that festival on what sits behind a Rhode Island dispensary counter today, and you would need a different plan. Flower in the legal market routinely tests above twenty percent. Concentrates, waxes, shatters, and vape oils run 80 to 90 percent. That is not a stronger version of the same drug. It is a different drug wearing the same name.
I spent twenty years in law enforcement. I commanded the Investigative Services Division, worked narcotics, and served on the Organized Crime Drug Enforcement Task Force with the FBI and DEA. I know what that war cost: lives derailed over a bag of dope, informants burned, and whole neighborhoods policed into resentment over a plant that never justified the effort.
I do not want prohibition back. I supported legalization, and I still support it. That is precisely why the potency question deserves an answer.
Legalization was sold to voters on an image: a joint passed at a concert. What got built instead was a competitive retail industry with every incentive pointed at a single number on the label. Price tracks THC percentage. Breeders select for it. Some testing labs, under pressure to keep their clients happy, report a percentage the flower in the package cannot support.
Here is where an investigator’s habits matter. The question is never whether a supporting study exists, but what the whole body of evidence tells us.
It tells us this much. The EU-GEI study published in Lancet Psychiatry in 2019 found that daily cannabis users had roughly three times the odds of a psychotic disorder, and daily users of high-potency cannabis nearly five times. The effect scales with dose, which is what you look for when separating cause from coincidence.
After Canada moved to commercial sale, emergency department visits for cannabis-induced psychosis rose about forty percent, concentrated among adults nineteen to twenty-four.
It will not carry everything. Serious work cuts the other way, including a large analysis of insurance claims finding no association between legalization itself and psychosis-related care. Cannabis is not the sole cause of anyone’s schizophrenia, and most people who use it will never develop one. Anyone who tells you the science here is settled is selling something, and that holds on both sides.
But regulation has never required certainty. It requires a plausible risk, an identifiable vulnerable population, and an intervention cheap enough to try. We have all three.
We also know how to do this, because we do it with alcohol every day, and nobody calls it prohibition. Beer, wine, and spirits are labeled by proof, taxed by proof, and served by people trained to notice when a customer has had enough. A bar that poured grain alcohol into a pint glass and charged beer prices would lose its license by the weekend.
Cannabis regulation went the other direction. Rhode Island caps THC in edibles at ten milligrams per serving and one hundred per package, which is sensible, then sets no ceiling at all on flower or concentrates, which is where the pharmacology actually lives. Our neighbors noticed. Connecticut caps flower at thirty-five percent and require a psychosis warning label above thirty. Vermont caps flower at thirty percent and solid concentrates at sixty, and spent this session brawling over whether to lift them. Rhode Island sits between them with no cap at all.
Three fixes are worth the General Assembly’s attention, and not one recriminalizes anything. Set a ceiling on inhalable concentrates: a cap on flower potency is largely symbolic, since the plant tops out near 30%, but concentrates are a manufacturing decision, and manufacturing decisions can be regulated. Tax by milligram of THC rather than by price, because our tax code as written quietly subsidizes potency.
Connecticut tried exactly that and will drop it on October 1, which the industry will cite as proof the idea fails. It does not. Connecticut set its rates in cents per milligram and then watched the average price of a gram fall by more than 40%, turning a modest levy into an effective rate approaching 35% on some products. That is a failure to index a rate, not a failure of the principle. And require honest labeling, backed by random state audits and real penalties for laboratories that inflate results.
The people who were at Woodstock are grandparents now. Many see legalization as an argument they finally won after fifty years of being called criminals, and they are not wrong. But the product they won the argument over is not the product on the shelf. Regulating potency is not a betrayal of legalization. It is the part we skipped.
Sources
Cannabis at Woodstock, one to three percent THC
University of Mississippi Potency Monitoring Program, the DEA-funded series analyzing seized samples since the early 1970s. Figures summarized in Smart Approaches to Marijuana, “Marijuana Potency: More THC, Increased Use, Greater Harm.” learnaboutsam.org
Flower above twenty percent, concentrates at eighty to ninety percent
Finn KP, Murray RM, et al. “Cannabis, psychosis, and violence: case reports and comprehensive evidence review.” Frontiers in Psychiatry, vol. 17, 2026. doi:10.3389/fpsyt.2026.1824748
Laboratories reporting potency the flower cannot support
Schwabe AL et al. “Uncomfortably high: Testing reveals inflated THC potency on retail Cannabis labels.” Twenty-three samples from ten Colorado dispensaries; observed potency averaged 14.98 percent, with roughly seventy percent of samples testing more than fifteen percent below label. PMC10096267
Odds of psychotic disorder among daily and high-potency users
Di Forti M, et al. “The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study.” Lancet Psychiatry 2019; 6:427–436. Daily use OR 3.2; daily high-potency use OR 4.8
Emergency department visits after Canadian commercialization
Myran D, et al. “Association between non-medical cannabis legalization and emergency department visits for cannabis-induced psychosis.” Molecular Psychiatry, 2023. IRR 1.30 overall for the commercialization period; IRR 1.63 for ages nineteen to twenty-four
Evidence cutting the other way
“State Cannabis Legalization and Psychosis-Related Health Care Utilization.” Analysis of commercial insurance claims finding no association between state legalization and psychosis-related care. PMC9925044
Rhode Island edible limits
Rhode Island Cannabis Control Commission regulations, 230-RICR-80-10. Ten milligrams per serving and one hundred per package for cannabis edibles; separate and lower limits of one milligram per serving and five per package apply to hemp consumables
Connecticut potency caps and warning label
Public Act 26-8 (HB 5350) and HB 5222, 2026 session. Flower capped at thirty-five percent; concentrate cap eliminated effective October 1, 2026; high-potency psychosis warning extended to plant material above thirty percent total THC. Shipman & Goodwin, “Market-Moving Changes for CT Cannabis Ahead,” May 8, 2026. On the April repeal and May reinstatement of the flower cap: CT Mirror, May 6, 2026
Vermont potency caps
Act 164 of 2020 and subsequent amendments; flower capped at thirty percent, solid concentrates at sixty. On the 2026 fight over S.278: Compass Vermont, May 21, 2026. On the rejected fifteen percent proposal: Vermont Cannabis Control Board, “Response to 15% THC Cap Recommendation”
Connecticut abandoning the potency-based excise tax.
Rates through September 30, 2026: $0.00625 per milligram of THC for plant material, $0.0275 for edibles, $0.009 for other products. Replaced October 1, 2026, by a flat 10.75 percent excise on gross receipts under Public Act 26-8. Average price per gram fell from $12.51 in March 2024 to $7.22 in March 2026, driving effective rates toward 35% on some products while revenue rose 67% on nearly flat sales. MJBizDaily, August 2026; Tax Policy Center, “How do state and local cannabis taxes work?”
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