California appears poised to join the growing number of states that have legalized marijuana, even as the federal government is reaffirming its 46-year-old stance that pot is a top-tier illicit narcotic on par with heroin and LSD.

The Drug Enforcement Administration announced Thursday that marijuana will remain classified as a Schedule I controlled substance – a designation reserved for highly addictive drugs with no proven medical use.

Thousands of published studies and extensive anecdotal evidence have indicated marijuana can help with conditions such as epilepsy and chronic pain. But DEA acting Administrator Chuck Rosenberg said a thorough review of the research, with input from the U.S. Food and Drug Administration, determined cannabis treatments haven’t yet been proven effective by controlled clinical trials and widespread acceptance from the medical community.

“If the scientific understanding about marijuana changes – and it could change – then the decision could change,” Rosenberg said. “But we will remain tethered to science.”

Cannabis advocates said they don’t expect the DEA’s ruling to adversely affect various marijuana legalization votes on the ballot in California and seven other states this November. But the federal action underscored the continuing functional and financial limbo in which multimillion-dollar – or even multibillion-dollar – legal cannabis industries find themselves in two dozen states.

Cannabis growers, distributors and retailers can’t access banking services, forcing them to operate largely in cash. They can’t write off typical business expenses come tax time. Derek Peterson, CEO of Irvine-based Terra Tech, even got denied life insurance because of his involvement in the cannabis industry.

“Some sort of deal needs to be brokered to harmonize state and federal law so we’re not constantly battling each other,” said Aaron Herzberg, who runs the Costa Mesa-based marijuana real estate firm CalCann Holdings.

Until then, he said, the federal government’s view of pot will continue to diverge from that of the American public.

“The majority of citizens live in states where marijuana is available to people for medical purposes,” Herzberg said. “It seems like the DEA and federal government is just woefully behind the times and is not getting the message.”

The DEA did make one concession Thursday, saying it would remove the government’s monopoly on growing high-quality marijuana for research purposes. The policy has meant that since 1968, only the University of Mississippi could supply marijuana for FDA-approved studies.

The DEA insists it’s never turned down a request from qualified researchers to access that supply. But the agency acknowledged there’s mounting demand from researchers, so it’s going to allow more growers to apply to become federally sanctioned suppliers.

Dr. Igor Grant, a psychiatrist who oversees the Center for Medical Cannabis Research at UC San Diego, said he was reviewing the DEA ruling and couldn’t comment on whether his center would apply to grow cannabis. But he said he was encouraged by efforts to expand access for researchers.

“There is significant evidence that cannabis possesses therapeutic value, and it is worthy of continued, even accelerated, investigation and development,” Grant said. “Actions that reduce obstacles to conducting serious, rigorous science regarding the use of cannabis to treat diseases are a good thing.”

Terra Tech’s Peterson sees Thursday’s announcement on researching cannabis as long overdue. However, the federal government is being “hypocritical,” he said, by simultaneously asserting marijuana has enough potential medical benefits to justify changing research policies but also should remain a Schedule I drug.

Congress placed cannabis in that category in 1970. The drug’s classification has been reviewed periodically. The latest reexamination was prompted by a petition filed with the DEA five years ago by then-Washington state Democratic Gov. Christine Gregoire and then-Rhode Island Republican Gov. Lincoln Chafee.

Gregoire said Thursday’s action was “very disappointing” and “puts the DEA totally out of touch with the Justice Department, current research, the medical profession, patients and the public.”

Roughly 80 percent of Americans believe medical marijuana should be legal, according to recent polls. And the plant can be used to treat ailments in 25 states.

Recreational use is allowed in four states plus Washington, D.C. If California passes Proposition 64 this November, 1 in 6 Americans would live in a state where adults would be allowed to freely use cannabis.

Marijuana opponents predict the DEA’s latest decision will slow that momentum.

“To be honest, it vindicates us,” said Kevin Sabet, president of Smart Approaches to Marijuana, which has donated $64,150 to fight Prop. 64.

Many advocates disagree, saying the federal government’s action may well motivate states to press ahead with their own expanded cannabis programs.

“The federal government has, to some extent, become highly irrelevant in the conversation about legalizing marijuana,” Herzberg said. “This doesn’t slow down anything as far as legalization on a state level in California or anywhere. But it’s just disappointing.”

The ruling will intensify pressure on Democratic presidential candidate Hillary Clinton to follow through on her promise to recategorize marijuana if she reaches the White House.

President Barack Obama also could face added pressure to override the DEA’s decision before his term expires at the end of the year.

His administration drew praise from many pot backers three years ago when the Justice Department said states could proceed with sales of marijuana, as long as they adequately regulated the industry. But U.S. Rep. Dana Rohrabacher, R-Costa Mesa, who recently acknowledged that he uses a medical marijuana cream to ease his arthritis, said the president hasn’t gone far enough.

“The Obama administration has had the chance to correct a foolish and counterproductive policy,” he said. “Now it’s up to the Congress and the next administration.”

Tribune News Service contributed to this report.

Contact the writer: bstaggs@scng.com