(CNN) – Marijuana will remain a schedule l controlled substance, which declares it has "no currently accepted medical use and a high potential for abuse," the Drug Enforcement Administration said Thursday.
This keeps the drug in the same category as heroin and cocaine.
The announcement is in response to two recent petitions asking the agency to reconsider this designation for the benefit of scientific research.
The decision is based on a "scientific and medical evaluation" conducted by the US Food and Drug Administration at the request of the DEA.
"The DEA and the FDA continue to believe that scientifically valid and well-controlled clinical trials conducted under investigational new drug (IND) applications are the most appropriate way to conduct research on the medicinal uses of marijuana," said a statement from the DEA.
The agency is taking a step to make the plant more available for research. Since 1968, the University of Mississippi has held the only license issued by the DEA to grow marijuana for research, which is funded by and produced under a contract from the National Institute on Drug Abuse. Now, more universities will be able to grow the plant for research. The DEA said this "will allow additional entities to apply to become registered with DEA so that they may grow and distribute marijuana for FDA-authorized research."
The agency said it has never stood in the way of a researcher conducting an FDA-approved study using marijuana from the NIDA-approved supply of the plant.
According to the DEA, as of June, there there were 483 researchers registered with the agency to conduct FDA-approved research with schedule I controlled substances, not just marijuana.
The agency maintains its "commitment to work together with the FDA and NIDA to identify ways of streamlining research on marijuana and its extracts."
But advocates, including researchers and patients, want more. Rep. Earl Blumenauer, D-Oregon, said in a statement, "this decision doesn't go far enough and is further evidence that the DEA doesn't get it. Keeping marijuana at schedule I continues an outdated, failed approach -- leaving patients and marijuana businesses trapped between state and federal laws."
At least 25 states and the District of Columbia have approved the use of medical marijuana for conditions ranging from epilepsy to arthritis.