Optimistic activists would say that the movement for marijuana legalization made a small gain last week when the Drug Enforcement Administration decided to expand marijuana research. But Sanjay Gupta - a neuroscientist who produced the Weed documentary series for CNN - suggests that the DEA's move probably won't make a big difference. In fact, new research projects might be geared toward reaffirming rather than challenging biases against cannabis.

Last week, DEA chief Chuck Rosenberg denied an application to loosen America's marijuana laws. Right now, cannabis is listed as a Schedule I drug in the Controlled Substances Act (CSA). That means the federal government defines it as a substance that has no medical value and is as dangerous as heroin. For decades, advocates have fought to have cannabis dropped to Schedule II so that it can be recognized as medicine. That change would basically mean downgrading cannabis from being considered as dangerous as heroin to as dangerous as methamphetamine, methadone and cocaine (other Schedule II's). So re-scheduling wouldn't be revolutionary, but it could open the door to legalizing medical marijuana at the federal level.

That change was apparently too much for the DEA. Rosenberg refused to re-schedule cannabis. But he did pledge to help researchers by letting more labs grow cannabis for scientific study. Until now, only the University of Mississippi was legally allowed to grow research-grade marijuana in America. And the stranglehold on supply has delayed progress in cannabis research.

So will expanding the number of growers help? That's "unlikely," according Gupta, who published a CNN commentary on the DEA's decision. He says that increasing the number of studies won't help unless researchers are allowed to examine the benefits of cannabis. After a quick curation of the U.S. National Library of Medicine's journal database, Dr. Gupta found that 1,434 papers on medical cannabis have been published in the last five years. Of those, only 57 papers examined the benefits of medical marijuana. That's about 4 percent of approved studies.

"The vast majority," Gupta wrote, "were research into the harm of marijuana, such as 'Bad trip due to anticholinergic effect of cannabis,' 'Cannabis induced pancreatitits' and 'Marijuana use and risk of lung cancer.'"

Gupta says the problem stems from a different type of stranglehold on supply - bureaucratic oversight. Before beginning a study, cannabis researchers typically need to get permission from the National Institute on Drug Abuse (NIDA). And - as their name suggests - NIDA is invested in the addictive properties of substances like cannabis, not its potential benefits.

"The institute has a primary mandate to study substances for potential abuse rather than as a medicine... Even if a study does cross all the hurdles [to get access to research-grade cannabis], the door may stay locked if the intent is to study the benefits of medical marijuana as opposed to the harm, " wrote Dr. Gupta.

So we might not see substantial cannabis reform in America unless another organization holds the key to unlocking research. For more, check out Gupta's full article.

Banner image: Dr. Sanjay Gupta at the Stand Up To Cancer event at Sony Pictures Studios, Culver City. September 10, 2010 Culver City, CA (Featureflash Photo Agency / Shutterstock.com)