The notice from the DEA spelled out three reasons why marijuana would not be rescheduled: a potential for and history of abuse and addiction, lack of accepted medical use, and a lack of safety information. The last two reasons are part of the drug’s failure of a five-part FDA test that states that for a medicinal drug “the drug’s chemistry must be known and reproducible,” “there must be adequate safety studies,” “there must be adequate and well-controlled studies proving efficacy,” “the drug must be accepted by qualified experts,” and “the scientific evidence must be widely available.” The clinical data that could even meet the FDA’s review standards was subject to intense scrutiny. In the end, the FDA could only find 11 research articles that met its review qualifications of being randomized, double-blind, placebo-controlled clinical studies.
While these 11 studies did demonstrate marijuana’s efficacy in decreasing pain, stimulating appetite for HIV patients, reducing spasticity in patients with multiple sclerosis, and easing the symptoms of glaucoma, the FDA report qualifies them as “proof-of-concept” studies without proper sample size, standardization of marijuana dosages, and control of pre-experiment exposure to marijuana.
The decision by the DEA still keeps over 40 states and the District of Columbia that allow some form of medical-marijuana usage in technical noncompliance with federal law. The decision itself also inhibits legitimate clinical research that could remedy the FDA’s lack of data. While the DEA has approved a recent study of medical marijuana in treating veterans with post-traumatic stress disorders and in 2015 relaxed its requirements for medical testing on cannabidiol marijuana extracts, the process for determining medical efficacy is complicated and difficult.
Investigators have to first apply to the Food and Drug Administration for a license to use small amounts of a single research-approved strain grown at the University of Mississippi. Federal gatekeeping is “reluctant to support medical research and has historically focused its efforts (almost) exclusively on demonstrating the drug’s harmful effects,” according to investigators. Even if that hurdle is crossed, researchers face lengthy and and expensive security measures and background checks from the DEA.*
Marijuana’s promise as a therapy has been acknowledged by several states. It also has potential effects in making health-care cheaper and easing the opioid crisis—which has itself been cause by people's dependence on several Schedule II drugs. But in order to meet strict DEA and FDA standards, more researchers will have to navigate a system that appears to discourage research. Until that burden is met, or until Congress changes scheduling laws, it appears the uneasy truce between state decriminalization of marijuana and its federal status as an illegal drug will continue.
* This article originally stated that investigators applied directly to the National Institute on Drug Abuse. We regret the error.