Here are NIDA’s Cannabis Research Priorities

Cannabis might still be federally illegal, but federally funded researchers are increasingly thinking about the plant, its components, and how changing cannabis laws are affecting Americans in the short and long-term. 

In October, Colorado State University Pueblo continued its Institute of Cannabis Research series with Susan Weiss, the director of the Division of Extramural Research at the National Institute on Drug Abuse (NIDA), co-hosted also by the Lambert Center for the Study of Medicinal Cannabis and at Thomas Jefferson University (read Cannabis Wire’s previous coverage of CSU Pueblo’s series). 

Weiss gave a presentation called “Cannabis Research and Policy: State of the Science,” which covered, among other things, the areas of research that NIDA has been supporting, as well as cannabis policy changes underway that NIDA is “concerned about.” Weiss, who serves as the senior science advisor to NIDA director Nora Volkow, also talked about how NIDA approaches messaging on cannabis to the public. 

Weiss framed the discussion by reminding those in the audience that cannabis is the “most commonly used early illicit drug in the U.S.,” as nearly 32 million Americans aged 12 and older have reported that they used cannabis in some form in the past month. 

One area where NIDA is focused includes studies on the long-term health effects on teenagers and pregnant people. Weiss discussed the National Survey on Drug Use in Health, which is a national survey that looks at cannabis use by age group (12 to 17, 18 to 25, and 26 and older). When it comes to 12-17 year olds, Weiss said, use has remained fairly steady as legalization laws have been implemented from coast to coast. But the 18-25 year-old group has seen increases, as well as the 26 plus group. (In every adult use state, the legal age is set at 21.) 

“This is really an important finding because it’s quite consistent,” Weiss said, adding that because of the way that the survey is structured, it’s unclear how cannabis use is changing in the 55 and older group. “I think in some ways, that may be a population where use is changing and where there may be particular worries.” 

The survey also covers frequency of cannabis use. In 2002, for example, roughly 14.6 million people reported past month cannabis consumption, with about one-third of that group consuming 20 or more days a month. In 2019, “we have almost double the number,” Weiss said, with about 40% of that group in the 20 days plus cohort. 

While these national surveys provide a trove of data, there’s much-needed room for improvement, Weiss said. 

“They’re also not necessarily giving us the sort of granularity that we need, particularly in today’s marketplace,” she said, noting that the surveys aren’t covering things like people who consume cannabis “all day,” or those who only consume a tiny bit before bed. 

One area that NIDA is watching is in the “perceived harmfulness of regular” cannabis consumption, which in the 12-17 group has been dropping over time.

“The are not showing increased use at this time, but they certainly don’t view it as particularly harmful,” Weiss said. 

Weiss also mentioned the Marijuana Potency Monitoring Project, which NIDA has supported for years, through the University of Mississippi (which was for decades, until this year, the only federally-approved site for cannabis cultivation in the nation). The data analysis of seized samples from the illicit market show that THC content has risen, while CBD has either remained steady or dropped. 

This doesn’t account for the cannabis products sold by state-licensed operators in state-legal shops.

“It’s something that we’re starting to look at,” Weiss said, adding that NIDA’s “understanding” is that these products are also of increasing THC content.

While the Drug Enforcement Administration has finally moved to license additional cannabis cultivators to grow for research purposes, that process was delayed for nearly half a decade. 

“We’re very happy that that has happened,” Weiss said. “We’ve tried to diversify the types of cannabis that we have available for research, but we’re still limited relative to what is out there. And having additional growers, I think, might be able to really help expand the types of research that we can do, both for medicinal use, just as well as effects.”

Weiss returned to cannabis use during pregnancy, and talked about how those studies, which have used both self-reported and toxicology data, show that cannabis use is “not a very high percentage.” But the group remains in the high risk pool and therefore a concern to NIDA. It’s been well-documented that THC crosses the placental barrier and that prenatal exposure to cannabis is linked to, for example, lower birth weight, though some longer term effects are unclear. One hurdle for researchers in this area is that pregnant people might be hesitant to self-report their cannabis use. 

And, researchers don’t really know what kinds of cannabis products pregnant people might be consuming. 

“We also need much better quantification of exposure to THC or the other components we know now,” Weiss said. “There are so many different products that are available to people, and most of the research is focused on THC or CBD, but the products contain combinations of these particular cannabinoids, as well as all the other different types of cannabinoids.” Weiss also highlighted the need to know more about how cannabis might affect sperm, given that some data show that THC can cause epigenetic changes in sperm cells. 

One major study just kicked off weeks ago, called the Healthy Brain and Child Development study, funded in part by the NIH HEAL Initiative (HEAL stands for “Helping End Addiction Long term”). The study, part of Congress’ effort to combat the opioid epidemic, will include 7,500 participants and will follow infant brain and behavioral development through age 10, and will include cannabis exposure. 

And, while men have historically consumed cannabis more than women, that might now be changing, Weiss said. 

“I think females are now starting to catch up to males, possibly because of the changes in the societal view on using marijuana,” Weiss said. 

Weiss also talked briefly about the industry. As Cannabis Wire has reported extensively, the hemp industry is eagerly — if not impatiently — awaiting rules on hemp-derived cannabinoid products, such as CBD products, from the Food and Drug Administration (though, federally, the growing is regulated through the U.S. Department of Agriculture). In the meantime, the CBD market, which Weiss called “a bit of a mess,” has gone mainstream, and global.

“Right now, we’ve got a multibillion dollar industry, which is very unregulated. And the concerns with this particular market are the fact that we have unregulated products, which a number of studies have shown contain other things besides the CBD that they’re supposed to contain,” Weiss said. Additionally, there are many unverified health claims on the labels of some CBD products, which is a particular challenge when, Weiss said, “there are uninformed users.” 

“They don’t really know what they’re getting. They don’t really know if there are side effects. They should watch out for drug interactions,” Weiss said. 

Weiss called for public education campaigns to coincide with changing of any cannabis policies, along with the collection of baseline data. 

“I think we have a public experiment that’s still in its early stages, especially related to the high potency product. There’s a lot of media that’s pushing for the safety of cannabis and its medical uses,” Weiss said. “We don’t yet know what full commercialization will mean, especially if we get the industries involved. So, I think that science can inform policy. I think we need to acknowledge that this is a very polarized issue. We need to be explicit about what we know and what we don’t know.” 

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