At the same time Californians are preparing to vote on the legalization of adult marijuana use, the federal government is weighing whether pot should continue to be classified as a top-tier narcotic on par with heroin.

Within a month, the Drug Enforcement Administration is expected to release a much-anticipated decision that could alter cannabis’ ranking in the hierarchy of controlled substances – a formal listing that affects everything from medical research to taxing policy.

Since the list was created in 1970, marijuana has been ranked in Schedule I – the most restrictive category – alongside heroin, LSD and peyote. The designation is reserved for drugs the DEA says have no proven medical use and are highly addictive.

“We’re bound by the science,” said Melvin Patterson, a spokesman for the DEA.

But many experts and advocates say the current classification is increasingly at odds with scientific studies on marijuana, which suggest the drug has medical value in treating chronic pain, seizures and a number of other conditions, with a lower addiction rate than alcohol.

The DEA ranking also lags behind a growing public consensus. Roughly 80 percent of Americans believe medical marijuana should be legal, according to recent polls, and some 60 percent support legalizing the drug for all adults.

“In 2016, this notion that cannabis possesses potential harms equal to that of heroin … simply doesn’t pass the smell test,” said Paul Armentano, deputy director of the National Organization for the Reform of Marijuana Laws, or NORML.

Medical marijuana is legal in 25 states. Recreational use is allowed in four states plus Washington, D.C. If California approves recreational use in November, 1 in 6 Americans will live in a state where adults would be allowed to freely use cannabis.

The question of how cannabis should be ranked has been hotly debated since Congress placed it in the Schedule I group when it passed the Controlled Substances Act nearly 46 years ago. The drug’s classification has been reviewed periodically, with the latest re-examination prompted by a petition filed with the DEA five years ago by the then-governors of Rhode Island and Washington.

In April, the DEA advised Congress that it expected to announce a decision in the first half of 2016.

Patterson said officials now “clearly anticipate something happening in the next month.”

OPTIONS ON THE TABLE

The agency has several options: Keep cannabis as a Schedule I drug; reclassify some or all of its compounds to a lower schedule; or remove the plant from the controlled substances list altogether.

There is a greater chance than ever that marijuana will be rescheduled, said John Hudak, who studies the topic as a deputy director with the Brookings Institution. But he still expects pot to remain a Schedule I drug.

“It needs to cross a threshold that says it has an accepted medical value,” Hudak said. “While there are plenty of patients and doctors who do believe it has medical value, that’s not a universal belief in the medical community.”

Leslie Bocskor, president of Las Vegas-based cannabis advisory company Electrum Partners, thinks the odds slightly favor a reclassification of marijuana to Schedule II. That category includes morphine and cocaine, which the DEA says are highly addictive but have some medical value. A form of cocaine, for example, is used by some dentists as a local anesthetic.

The least restrictive of the five schedule categories, Schedule V, includes cough syrup with a bit of codeine.

Alcohol and tobacco aren’t included on the DEA’s controlled substances list, even though federal studies have found both are associated with higher dependency rates than marijuana.

Patterson said the DEA frequently hears from people frustrated that marijuana hasn’t been rescheduled sooner.

“They have their mind made up on what marijuana does in the short term,” he said. “But what about different strains? What about 10 years from now or even 20 years from now? Long-term effects matter.”

WHAT RESCHEDULING WOULD DO

For the medical marijuana community, even reclassifying cannabis as a Schedule II drug would offer some vindication.

“At a minimum, it would bring an end to the federal government’s long-standing intellectual dishonesty that marijuana ‘lacks accepted medical use,’” NORML’s Armentano said.

Such a shift by the the DEA also might offer a small boost to at least half a dozen states with medical or recreational marijuana initiatives on the ballot this November.

That potential to give some credence to legalization efforts is one of the reasons a few members of Congress, including Sen. Chuck Grassley, R-Iowa, and the organization Smart Approaches to Marijuana cite in arguing against reclassifying marijuana.

“Rescheduling would simply be a symbolic victory for advocates who want to legalize marijuana,” SAM wrote in a policy paper on the issue.

But both the California and American medical associations say rescheduling pot could lower the barriers a bit for federally sanctioned drug research.

The DEA never has turned down a marijuana research request that met federal criteria, Patterson said. But experts say red tape related to Schedule I drug research is so formidable that it discourages applications. So though there are tens of thousands of peer-reviewed studies on marijuana, there are few costly and rigorous double-blind, placebo-controlled trials involving cannabis.

Moreover, researchers say, marijuana studies are saddled with restrictions that don’t apply to other Schedule I drugs.

Since 1968, for example, the federal government has said only a tightly controlled stock of high-quality marijuana grown under contract by the University of Mississippi can be used for FDA-approved studies. Armentano said that restricts the supply available for research.

If marijuana is reclassified to at least Schedule III – alongside Tylenol with codeine and anabolic steroids – it would mean the nation’s rapidly growing number of cannabis-related businesses could begin deducting operating expenses from their federal taxes.

Under a tax rule imposed during the war on drugs by President Ronald Reagan’s administration in the 1980s, businesses dealing in Schedule I or II substances are prohibited from writing off common expenses such as rent, utilities or advertising.

Harborside Health Center, a large Oakland dispensary, has been battling the IRS over the rule for five years after being assessed $2.4 million for illegal deductions. A decision in that case is expected soon.

WHAT RESCHEDULING WOULDN’T DO

Even if cannabis is moved down the controlled substances list to the least-restrictive category, the industry still would be likely to face business and regulatory hurdles.

Armentano likened such a change, should it come, to the first stride in a marathon.

“Technically, it gets you closer to the finish line,” he said. “But you still have a whole hell of a long way to go.”

Pot would remain an illegal substance under federal law. Reclassification wouldn’t necessarily open access to banking services, Brookings’ Hudak said. And doctors wouldn’t automatically switch to writing prescriptions, as opposed to “recommendations,” for medical marijuana, since that’s allowed only for FDA-approved drugs.

“There are certain people who play up rescheduling as an earth-shattering reform,” Hudak said. “It is not.”

He said sweeping changes would come only in the unlikely event that cannabis is completely descheduled, putting it on par with alcohol.

That would allow local governments to create cannabis policies free from federal interference, Armentano said, the way they can set their own hours for when bars stop serving alcohol or make entire counties “dry.”

Armentano isn’t optimistic the DEA will move marijuana to a less restrictive category, but he said there has been one positive result from the current review.

“There’s attention being paid to how they handle this situation in a way that just wasn’t there before,” he said. “If the DEA goes down the same path as it has in the past, I think they’re going to have some explaining to do.”

Contact the writer: 714-796-7963 or bstaggs@ocregister.comTwitter: @JournoBrooke