The National Institute on Drug Abuse (NIDA) has awarded researchers a $2.9 million grant to study how to improve the efficacy of cannabis warning labels, a project that will involve interviews with state marijuana regulators and online experiments designed to develop and implement “more effective warning labels that inform people about the risks associated with cannabis use.”
“The study will analyze current warning regulations and test different warning characteristics on newly developed cannabis warning labels to see which warning characteristics are most effective in communicating the harms of cannabis use,” says a press release about the federally funded project from UNC Health, where the researchers are based. “The research team will work with state regulators to ensure the newly developed cannabis warnings address current issues and challenges facing state regulators.”
Warnings developed through the investigation will be shared with marijuana regulators at the state level “to contribute to evidence on the impact of state policies on cannabis use,” the release adds, “which is a priority” for NIDA.
The project is jointly led by co-principal investigators, Leah Ranney, a UNC medical school research professor and director of the the University of North Carolina’s Tobacco Prevention and Evaluation Program, and Sarah Kowitt, a professor of family medicine at the UNC’s medical school.
“With the increase in state legalization for cannabis products and the rise in cannabis use among young adults and adults, we recognized the need to balance information on cannabis benefits that are widely advertised with the potential for harm via warnings,” Ranney told Marijuana Moment in an email. “Our experience and expertise in tobacco product warnings perfectly position us to develop clear and effective cannabis product warnings.”
The study, she added, is focused on measuring how well warnings educate consumers about possible harms, not whether warnings influence their behavior.
“Our study aims to develop effective cannabis warnings that inform consumers about the potential risks of cannabis use,” Ranney said. “To accomplish this goal, we must identify which warning characteristics capture attention and are easily recalled.”
Kowitt said in a statement that the study is the first of its kind on cannabis warnings.
“Throughout the five years of the grants, we will examine how states have implemented regulations on warnings for cannabis product packages, experimentally develop a set of evidence-based cannabis warnings, and examine whether larger evidence-based warnings outperform existing warnings on product packages,” she said. “These findings will be very useful to state regulators who have been tasked with setting their own regulations for cannabis warnings, often without a rigorous evidence base.”
Other members of the research team include public health specialist Kristen Jarman of UNC Family Medicine; lawyer Rachel Callanan of the Public Health Law Center; Gillian Schauer, executive director of the Cannabis Regulators Association (CANNRA); and epidemiologist Julia Dilley of the Oregon Health Authority.
The study is needed, the UNC Health release says, because “current cannabis warning labels are small, difficult to read, and hard to understand.”
“Cannabis is the third most commonly used substance in the U.S., with almost half of all adults admitting to trying it,” it says. “It can cause physical harm, like chronic bronchitis, cognitive impairment, such as memory loss, and other types of risks, including car crashes. Despite these harms, many people don’t know or underestimate the risks.”
Early last year, the National Transportation Safety Board (NTSB) urged states where marijuana is legal to include warning labels on cannabis products that caution against driving while under the influence—noting that federal prohibition is a barrier to nationalizing such consumer education to mitigate public safety risks. The board recognized at the time that several legal states already require such labeling, but others don’t.
Because marijuana remains federally prohibited, “there is no federal requirement for labeling cannabis,” the NTSB report said. As such, the body didn’t propose a federal labeling requirement, instead saying that states should take lessons from other states and Canada, where cannabis is legal nationwide, to develop warning labels that explicitly discourage impaired driving.
Meanwhile, there is a standardized warning label for alcohol in the U.S. that’s mandated under a federal law enacted in 1988, the report notes. And while “evidence suggests that alcohol labeling had little effect on behavior change, some authors have suggested that even small effects can be meaningful if a product is widely used.”
“A recent study found that among the 31 U.S. states with medical cannabis programs, all have some labeling requirements, and 26 have some requirement for labeling concerning impairment, but not necessarily driving impairment,” the transportation board said.
One obstacle to labeling is ongoing confusion over what, precisely, the impacts and risks of cannabis might be.
A Congressional Research Service report from 2019 found that while “marijuana consumption can affect a person’s response times and motor performance…studies of the impact of marijuana consumption on a driver’s risk of being involved in a crash have produced conflicting results, with some studies finding little or no increased risk of a crash from marijuana usage.”
Another study that was published in 2022 found that smoking CBD-rich marijuana had “no significant impact” on driving ability, despite the fact that all study participants exceeded the per se limit for THC in their blood.
Asked about the shifting scientific views on cannabis and how that might affect the warning label project, Ranney said the work acknowledges that the “science on the health effects of cannabis is still evolving.”
“We will use the best science available when developing the warning content,” she wrote. “Our research study will be funded for five years, and we expect the science of cannabis health effects to advance as we develop these warnings.”
In August of last year, meanwhile, a coalition of marijuana reform organizations called on regulators across the world to adopt a universal symbol for marijuana products in the interest of promoting safety in the evolving cannabis market and making it easier to facilitate interstate commerce if states choose to enact that policy.
The groups said in a letter to regulators that there should at least be uniformity in labeling so that people know what products contain cannabis no matter where they’re shopping.
The International Intoxicating Cannabinoid Product Symbol (IICPS)—a yellow triangle with an image of a cannabis leaf and black border—has already been adopted by Montana, New Jersey, South Dakota and Vermont, while other states like Alaska are also considering it.
Doctors for Cannabis Regulation (DFCR), which played a leading role in developing the symbol and is spearheading the campaign for its universal adoption, said in a press release at the time its goal was “communicating a simple public health message,” which is: “Caution with cannabis.”
David Nathan, founder and president of DFCR, also criticized New York regulators in an op-ed for Marijuana Moment after the state moved forward with a more complex, individualized label for cannabis products despite being encouraged to follow the lead of other states and adopt the universal symbol.
The universal caution symbol, which was also developed in partnership with the standards organization ASTM International, intentionally omits letters, words or numbers to avoid language barriers, which would be especially important if it is used internationally. There would be space under the label on marijuana products where different jurisdictions could include additional text-based information that fits their needs.
David Vaillencourt, vice chair of the ASTM International Committee D37, said at the time that ASTM has long worked with the National Conference on Weights and Measures (NCWM), which had recently adopted national standards for cannabis packaging, labeling and storage.
NCWM considered adopting guidance calling for a universal label on cannabis products, but earlier this year opted to forego that plan because members were concerned that the body, which focuses primarily on scientific measurement, lacked the necessary health expertise to craft an appropriate label.
A representative told Marijuana Moment earlier this month that the NCWM labeling proposal is “permanently dead.”
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Ben Adlin, a senior editor at Marijuana Moment, has been covering cannabis and other drug policy issues professionally since 2011. He was previously a senior news editor at Leafly, an associate editor at the Los Angeles Daily Journal and a Coro Fellow in Public Affairs. He lives in Washington State.
