Health Effects from Cannabis Addressed by THC Potency Caps

Whether or not cannabis is harmful to human health is a continuing question for researchers, as some studies say smoking can have therapeutic effects, while others say long-term cannabis smokers experience anxiety at higher doses. 

“There hasn’t been clear science showing demonstrated significant reason to suggest this is a dangerous substance,” said Rosalie Liccardo Pacula, Elizabeth Garett professor of health policy, economics and law at the University of Southern California.  

One thing is certain, THC, which is the main compound of cannabis that produces psychoactive effects, is getting stronger, and there is little regulation to control the market.  

Last week, a report issued from the Senate Drug Caucus suggests that THC caps to limit potency of cannabis products might help curb long term “chances of psychosis in those that have a predisposition to the disorder,” for those that use cannabis frequently.  

The Caucus is concerned that more Americans may develop a cannabis use disorder as cannabis use and potency is increasing based on national data. In 2019, of the 31.6 million people who reported having used cannabis in the preceding month, there were 4.8 million that reported having cannabis use disorder. 

Nearly 850,000 received some kind of treatment for cannabis use, but the report states research is needed as cannabis has been a difficult topic for researchers to study because it is classified as a controlled substance.  

“When we talk about people using cannabis, and we talk about how much cannabis they use, it’s not just enough to know, did you use cannabis, but we need to know what product they used,” said Pacula.  

Pacula said the biggest and fastest-growing segment of the cannabis market is in concentrates, where the average potency of the concentrate sold is 70% THC.  

Several states tried to place potency caps on cannabis products, like Florida where bill HB 1455 was proposed by Republican Rep. Spencer Roach in March proposing a potency cap in smokable flower to 10%. Today the typical level of THC in a medicinal cannabis plant is around 25% to 30%. 

“To my knowledge there isn’t anywhere, or anywhere in the world a credible scientific study that shows a medicinal value of THC in concentration over 10% so I think that’s why that’s the basis for the 10% cap on smokable that’s the science behind,” he said during a meeting of the House Health Care Appropriations Subcommittee. 

“Proponents of [the] cap pointed to studies that indicate that cannabis may lose some of its medicinal properties or even exacerbate the perception of pain at potencies that exceed 10%,” write researchers from the Caucus report. 

California tried to reduce serving size by changing the packaging of cannabis products with THC instead of imposing a cap. Many edibles can only be bought for 100mg of THC per package, or at 10mg for a single serving.  

Policies governing THC potency caps, while usually lacking in bipartisan support, also have a history of not being enforced when the bills are passed.  

“Unfortunately, with the exception of edibles, most of these caps have failed, whether they’ve been set too low, and the industry has countered them, or the argument is made that just placing a cap will encourage the black market,” said Pacula.  

“If we go down this road, if we start banning certain products, we get law enforcement back in the business of enforcing cannabis laws,” said Chris Lindsey, the director of the government relations of the Marijuana Policy Project in a written statement.  

The Marijuana Policy Project is a DC-based non-profit that assisted in the passage of 13 medical cannabis laws in the past 15 years, and the SAFE Banking Act, which passed through the House of Representatives on April 19 and prevents federal regulators from punishing financial institutions that provide services to state-legal cannabis businesses. Lindsey added that potency caps are “terrible policy” and that states are “just heading down the wrong path.”  

The project urges senators to oppose federal THC caps and product bans stating, “THC has proven medical benefits, including relieving nausea and appetite loss. THC limits leave patients behind that respond best to cannabis with higher proportions of THC,” the organization said in a written statement.

In states where cannabis has been legalized, an increase in hospitalizations and emergency department visits for heart attacks and cannabis-associated adverse effects has been observed, based on a written statement from the American Heart Association. 

The report from the Caucus calls for the NIH and the FDA to, “make a public recommendation as to whether states should cap the potency of products that may be sold in order to mitigate the public health consequences associated with high potency cannabis.”  

“We’re behind the game when it comes to the science… it’s going to be very difficult to establish clinically appropriate regulations on things like potency once the industry has already taken place because it’s – as we are seeing in states right now – Colorado, Washington, even Massachusetts – efforts to try to change the potency of products once you have the legal market are met with very significant – what’s the word? – resistance. And I’ll stop there,” said Pacula.