TRENTON -- The Obama administration will uphold the ban on researching the therapeutic benefits of marijuana, once again rebuffing requests to remove the plant from the list of the drugs, like heroin and LSD, that are considered to be the most addictive and lacking medicinal value.

On Thursday, the U.S Drug Enforcement Administration will publish a notice in the Federal Register, a compilation of government rules, that will announce its decision to keep marijuana as a "schedule 1" drug, according to the DEA website.

The decision will no doubt disappoint supporters who had hoped the federal government would finally allow research to determine cannabis' potential. Half of the states in the nation, including New Jersey, as well as Washington D.C. permit the cultivation and sale of marijuana for medical purposes.

Limited studies inside and outside the country have shown cannabis can reduce pain, nausea, and muscle spasticity. But it remains taboo among most physicians who want to see more rigorous studies demonstrating its benefits, and fear they'll jeopardize their license to prescribe medications.

"The DEA's decision flies in the face of objective science and overwhelming public opinion. The reality is that half of U.S. states have already passed effective laws allowing patients legal access to medical cannabis, and it is changing lives," National Cannabis Industry Association Executive Director Aaron Smith said in a statement Wednesday night.

"Continuing marijuana prohibition forces critically ill people to suffer needlessly, leaves life-changing treatments undeveloped, and keeps patients and providers in limbo between state and federal laws," Smith said.

Last week, the National Council on State Legislatures passed a resolution asking the federal government "to respect state marijuana laws...without federal interference.

Editor's note: An earlier version of this story incorrectly included cocaine as one of the DEA's "schedule 1 drugs," deemed to have no medicinal value and among the most dangerous. Cocaine is grouped among schedule II drugs, which are considered less dangerous.

Susan K. Livio may be reached at slivio@njadvancemedia.com. Follow her on Twitter @SusanKLivio. Find NJ.com Politics on Facebook.