Pictured: pills of the painkiller hydrocodone. (Toby Talbot, Associated Press file)

Sean Spicer correlated marijuana use to opioid addiction. Medical research is not on his side

The epidemic of opioid addiction in the United States has been well documented. A staggering 33,000 people died in 2015 from overdosing on prescription painkillers, heroin or similar drugs, on par with the number killed by firearms and in car accidents.

The epidemic is growing, but its general causes are not in dispute. Nearly all research on the issue shows that excessive and improper prescriptions are what’s causing more people to become addicted.

But White House press secretary Sean Spicer on Thursday appeared to link the surge in opioid abuse to another factor: recreational marijuana use.

During a press conference, Spicer said that he expects states to face “greater enforcement” of federal laws against marijuana under the Trump administration, even in places where it has been decriminalized, as The Washington Post reported. As a rationale, he cited the rise in illicit drug use.

“When you see something like the opioid addiction crisis blossoming in so many states around this country,” Spicer said, “the last thing we should be doing is encouraging people – there’s a federal law that we need to abide by when it comes to recreational marijuana and other drugs of that nature.”

It was an extraordinary statement for two reasons. First, marijuana has nowhere near the same addictive or potentially lethal properties that opioids do. Second, Spicer seemed to imply that recreational marijuana use could lead people to try more dangerous drugs — a controversial claim commonly called the “gateway drug” theory.

Spicer’s remarks drew rebukes from a chorus of outraged marijuana advocates. The press secretary “contradicted known science and medical research by tacitly pinning the blame for the country’s heroin problem on marijuana,” the pro-pot magazine High Times wrote. The National Cannabis Industry Association had a similar take. “Science has discredited the idea that marijuana serves as any kind of gateway drug,” executive director Aaron Smith said, “and the addiction and death rates associated with opioids simply do not occur in any way with cannabis.”

Washington Attorney General Bob Ferguson on Thursday vowed to push back on the administration’s possible crackdown in his state, which was among the first to legalize recreational marijuana. In a letter to the Department of Justice earlier this month, he argued that efforts to combat the opioid epidemic “will not be helped by a renewed law enforcement focus on marijuana.”

“To the extent that DOJ chooses to reallocate anti-drug resources,” he said, “we encourage it to work even more closely with the states to combat the opioid scourge.”

Little evidence exists linking marijuana use to the opioid crisis. Indeed, a growing body of research suggests that decriminalized marijuana is associated with lower rates of opioid abuse and fewer opioid-related fatalities.

A recent study from Columbia University’s Mailman School of Public Health involving data from 18 states found that those with medical marijuana laws experienced a reduction in opioid involvement in fatal car accidents, as The Post reported. Researchers said the conclusion was straightforward: “In states with medical marijuana laws, fewer individuals are using opioids.”

A more exhaustive study published in the prestigious JAMA Internal Medicine in 2014 found that annual overdose rates were nearly 25 percent lower in states with medical cannabis laws than those without them. The analysis of more than a decade of cause of death data showed that “such laws were associated with a lower rate of overdose mortality that generally strengthened over time,” the study found.

Some advocates have even gone so far as to propose using medical marijuana to treat opioid addiction. Last year, Maine considered allowing cannabis therapy for people experiencing opioid withdrawal. The state’s health department ultimately decided against it, saying there wasn’t enough scientific evidence to support the process. But the notion that marijuana could help alleviate the opioid epidemic is still on the table elsewhere.

In his press conference, Spicer said President Donald Trump saw a “big difference” between using marijuana for medical and recreational purposes.

“The president understands the pain and suffering that many people go through who are facing, especially terminal diseases,” he said, “and the comfort that some of these drugs, including medical marijuana, can bring to them.”

To Spicer’s credit, the evidence is thinner when it comes to the potential benefits of recreational marijuana. For one, it’s harder to research recreational use because marijuana remains a Schedule I controlled substance under federal law. And though the idea of marijuana as a “gateway drug” is often ridiculed among advocates, the National Institute on Drug Abuse says it may have some merit.

But there’s almost no evidence showing recreational marijuana use could drive up opioid abuse. A 2016 review of academic studies related to cannabis use dating back more than a decade found no credible reports tying marijuana use to the “initiation of use of opioids.” More broadly, the National Academy of Sciences’ Institute of Medicine has long held “there is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs.” A report released last fall even indicated that opioid use had dropped among young people as marijuana use has risen.

For Ethan Nadelmann, director of the Drug Policy Alliance, the disconnect is clear.

“Spicer,” he said, “has it exactly backwards.”