With all the news about CBD dominating medical marijuana headlines, THC — largely associated with getting people high — may be feeling a bit left out. But new research suggests its therapeutic effects could be crucial, even as CBD has recently stolen the spotlight with its myriad reported health benefits. THC, researchers argue in Scientific Reports, could be the real star when it comes to the health benefits of medical marijuana.
In a paper published on Monday, a team of researchers led by Sarah Stith, Ph.D., an assistant professor of economics at University of New Mexico, write that medical marijuana patients who consumed products with higher levels of THC — not CBD — report greater relief from their symptoms. All their data came from a 21-month study on 3,341 medical marijuana patients who recorded their experiences with the drug through a cell phone app called ReLeaf.
The app lets users track the severity of symptoms like anxiety or pain before, during, and after using cannabis products. It also collects user-submitted data on the type of product (flowers, concentrated extracts), how it’s used (smoked, vaped, lotion), and, crucially, whether it has high or low levels of THC or CBD. The app, according to the developers — some of whom are also this study’s authors — is meant to offer a comprehensive picture of how well medical marijuana products relieve various symptoms.
Does THC Reign Supreme?
The findings complicate the conversation about medical marijuana, as much of the recent discourse has focused on CBD and not on THC. The very first FDA-approved marijuana-derived drug, for example, was a CBD-based seizure drug called Epidiolex. In this study, though, good old-fashioned flowers — the marijuana buds that are usually smoked or vaped — seemed to provide the most relief. And the higher the levels of THC were, the more relief the participants reported.
The paper also shows that the CBD content of a product was not positively associated with symptom relief, though the authors stopped short of saying that this outcome proves the substance is not medically valuable.
“It is possible that while CBD may operate inconspicuously to improve certain health outcomes, the adjunctive consumption of THC is needed to consciously experience or be aware of such effects,” they write.
Some Important Caveats
There’s no question that it’s important to investigate all the cannabinoids that could offer therapeutic benefits — whether that’s THC, CBD, or one of the many others. But it’s also worth noting that in this study, three of the authors are employed by MoreBetter Ltd., the company that developed the ReLeaf App. In addition, while the paper is published in an open-access journal, the data it bases its analysis on are not freely available to the public.
The design of both the app and study seem biased toward quick symptom relief, thus excluding data on slower-acting forms of medical marijuana. The Releaf video below explains how users track symptom relief, on a scale from one through ten, over time, revealing how this bias may occur. Smoked or vaped marijuana takes effect rapidly (within seconds), whereas edible THC and CBD products can take one to two hours to do so. The study only includes data from sessions in which a symptom change was recorded within 90 minutes, so CBD, which is usually ingested orally, may not have been accounted for.
“It is possible that CBD has more latent effects than THC (e.g., expanding beyond the 90 minute observation window), has an impact on symptoms infrequently reported in our data, or that CBD’s effects may not lend themselves to perceptual detection and subjective reporting,” the team writes.
Nonetheless, they conclude:
Only THC potency levels showed independent associations with symptom relief and experiences of both positive and negative side effects, with higher levels resulting in larger effects. In contrast, we did not observe an independent link between CBD levels and any of the omnibus symptom effects measured in the current study across nearly 20,000 user sessions.
While it may be the case that THC deserves the same amount of research attention as CBD, it’s nearly impossible to tell from this study whether one is more important than the other. Perhaps future data, gathered in the lab rather than on a mobile app, will shed further light on the matter.
Federal barriers and logistical challenges have hindered measurement of the real time effects from the types of cannabis products used medically by millions of patients in vivo. Between 06/06/2016 and 03/05/2018, 3,341 people completed 19,910 self- administrated cannabis sessions using the mobile device software, ReleafApp to record: type of cannabis product (dried whole natural Cannabis flower, concentrate, edible, tincture, topical), combustion method (joint, pipe, vaporization), Cannabis subspecies (C. indica and C. sativa), and major cannabinoid contents (tetrahydrocannabinol, THC; and cannabidiol, CBD), along with real-time ratings of health symptom severity levels, prior-to and immediately following administration, and reported side effects. A fixed effects panel regression approach was used to model the within-user effects of different product characteristics. Patients showed an average symptom improvement of 3.5 (SD = 2.6) on an 11-point scale across the 27 measured symptom categories. Dried flower was the most commonly used product and generally associated with greater symptom relief than other types of products. Across product characteristics, only higher THC levels were independently associated with greater symptom relief and prevalence of positive and negative side effects. In contrast, CBD potency levels were generally not associated with significant symptom changes or experienced side effects.