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As of this article, 25 U.S. states and Washington D.C. have legalized medical marijuana to some degree. With these new laws come long lists of conditions that may be treated with cannabis. That varies from state to state, but includes everything from multiple sclerosis and cancer to Alzheimer's disease and rheumatoid arthritis. The federal Drug Enforcement Administration (DEA), meanwhile, continues to classify marijuana as a Schedule I drug alongside the likes of heroin and LSD. Why? Because, as they say, it has no medical value. "There are no adequate and well-controlled studies proving efficacy...and the scientific evidence is not widely available," the DEA announced in 2014.

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How can this be possible? Are the states using different scientific standards than the federal government? Well, yes. According to The New York Times, state policymakers have overwhelmingly backed up their laws with less-than-solid evidence from animal studies and anecdotes. It's a bad situation all around.

Want to conduct a study into the efficacy of medical marijuana? Sure, no problem. You just need to register with the DEA, submit a new drug application to the FDA for human trials, and get approval from the Department of Health and Human Services or the National Institutes of Health. After that, you just have to get your entire marijuana supply from the National Institute on Drug Abuse (NIDA). NIDA's mission is to "advance science on the causes and consequences of drug use and addiction" and "enhance public awareness of addiction as a brain disorder," so if you're trying to study the beneficial effects of cannabis, they probably won't be too keen on providing research materials. Such is the bureaucratic quagmire that marijuana researchers face. Clinical research into the cannabis-based seizure drug Epidiolex, for example, even required doctor interrogations with DEA agents and upgrades to hospital security cameras before researchers could use the drug, according to STAT.

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The former director of New Mexico's medical cannabis program, Dr. Steven A. Jenison, put it to The New York Times frankly: "It's one thing to say we need to have more research, and it's another thing to obstruct the research." Steps are being taken to loosen these research restrictions—in 2015, the DEA eased some regulations on researching CBD, one of the active ingredients in marijuana—but progress is slow so far. It doesn't matter if you're for or against medical marijuana, because without scientific evidence, neither position makes sense.

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