The regulatory obstacles to clarifying cannabis’ role in medicine
That currently there is limited or no evidence to support the use of medical cannabis for the treatment of neuropsychiatric conditions points to the inherent difficulties in conducting high-level research in this area.
“There’s a tremendous shortage of reliable data, largely due to regulatory barriers,” said Dr. Martinez.
Since 1970, cannabis has been listed as a Schedule I drug that is illegal to prescribe (the Agriculture Improvement Act of 2018 removed hemp from such restrictions). The FDA has issued guidance for researchers who wish to investigate treatments using Cannabis sativa or its derivatives in which the THC content is greater than 0.3%. Such research requires regular interactions with several federal agencies, including the Drug Enforcement Administration.
“It’s impossible to do multicenter RCTs with large numbers of patients, because you can’t transport cannabis across state lines,” said Dr. Wallace.
Regulatory restrictions regarding medical cannabis vary considerably throughout the world (the European Monitoring Center for Drugs and Drug Addiction provides a useful breakdown of this on their website). The lack of consistency in regulatory oversight acts as an impediment for conducting large-scale international multicenter studies on the topic.
Dr. Buhmann noted that, in Germany, cannabis has been broadly approved for treatment-resistant conditions with severe symptoms that impair quality of life. In addition, it is easy to be reimbursed for the use of cannabis as a medical treatment. These factors serve as disincentives for the funding of high-quality studies.
“It’s likely that no pharmaceutical company will do an expensive RCT to get an approval for Parkinson’s disease because it is already possible to prescribe medical cannabis of any type of THC-containing cannabinoid, dose, or route of application,” Dr. Buhmann said.
In the face of such restrictions and barriers, researchers are turning to ambitious real-world data projects to better understand medical cannabis’ efficacy and safety. A notable example is ProjectTwenty21, which is supported by the Royal College of Psychiatrists. The project is collecting outcomes of the use of medical cannabis among 20,000 U.K. patients whose conventional treatments of chronic pain, anxiety disorder, epilepsy, multiple sclerosis, PTSD, substance use disorder, and Tourette syndrome failed.
Dr. Freedman noted that the continued lack of high-quality data creates a void that commercial interests fill with unfounded claims.
“The danger is that patients might abandon a medication or intervention backed by robust science in favor of something without any science or evidence behind it,” he said. “There is no reason not to expect the same level of data for claims about cannabis products as we would expect from pharmaceutical products.”
Getting to that point, however, will require that the authorities governing clinical trials begin to view cannabis as the research community does, as a possible treatment with potential value, rather than as an illicit drug that needs to be tamped down.
A version of this article first appeared on Medscape.com.