Marijuana, in the opinion of the U.S. Drug Enforcement Administration, has no medical value and should not be legally prescribed by doctors.

On Thursday, the U.S. Drug Enforcement Administration denied a set of petitions from a nurse-practitioner and two former state governors to remove marijuana from its classification as a Schedule I drug under the Controlled Substances Act. The decision--long-awaited by pot businesses--means marijuana remains in the same category as substances such as heroin and LSD.

The DEA concluded that after scientific and medical evaluations and recommendations from multiple government health agencies, marijuana has "a high potential for abuse, has no accepted medical use in the United States, and lacks an acceptable level of safety for use even under medical supervision," according to the acting administrator of the DEA, Chuck Rosenberg.

Although the marijuana industry was hoping for a different result, it did get some good news: The DEA is ending the University of Mississippi's position as the only federally licensed operation for providing cannabis for research purposes. Russell Baer, a special agent at the DEA's office of public affairs, says that the DEA will be accepting applications from academic institutions and private entities to become DEA-approved bulk marijuana providers for the research community.

That might not seem like a major step toward relaxing pot laws, but according to John Hudak, a senior fellow at the Brookings Institute, it could open the door to eventually proving marijuana's benefits to regulators.

"Ending the DEA-mandated ... monopoly will mean that better, more careful, more precise, more theoretically-driven research can be conducted," Hudak wrote in a blog post. "If those studies show medical value, marijuana rescheduling will be more likely."