Is marijuana helpful for chronic pain?

A new study says no, reopening a fierce debate.

The research, published in the journal Lancet Public Health looked at a cohort of individuals with chronic, noncancer pain to see if marijuana was an effective treatment.

They also examined whether use of marijuana would decrease opioid use, a phenomenon known as an “opioid-sparing effect.”

The observational study took place in Australia beginning in 2012. It recruited 1,514 participants for a baseline interview.

The participants self-reported about their level of pain, opioid use, cannabis use, and mental health over the course of four years.

“We found no evidence that cannabis use improved patient outcomes. Those who used cannabis had greater pain and lower self-efficacy in managing pain. Furthermore, we found no evidence that cannabis use reduced pain interference or exerted an opioid-sparing effect,” wrote the study authors.

“Cannabis itself doesn’t seem to be promising for chronic pain treatment and side effects associated limit any benefits,” Dr. Nadya Swedan, a physical medicine and rehabilitation specialist at Lenox Hill Hospital, told Healthline.

Swedan was not involved with the Australian research.

Opioid-sparing effects of marijuana have become a frequent talking point in the United States as the nation struggles to find answers to its ongoing opioid crisis.

Recent studies have examined the correlation between legalized medical marijuana and opioid prescriptions.

That research concludes that legalized medical marijuana has led to a significant reduction in the number of opioid prescriptions where it’s available.

This recent study refutes that.

The debate erupts

The new research has caused a stir, with some experts and marijuana advocates questioning its methodology and conclusions.

“These conclusions are inconsistent with the large body of peer-reviewed science — including placebo-controlled clinical trial data — finding that cannabis is effective in pain management, particularly in the treatment of neuropathy, as well as numerous studies consistently finding that jurisdictions which permit legal, regulated cannabis access observe a significant decrease in patients’ opioid-related use, abuse, prescription drug spending, and opioid-related mortality,” said Paul Armentano, the deputy director of the National Organization for the Reform of Marijuana Laws.

Armentano told Healthline that the National Academies of Science has concluded that marijuana is considered to have “conclusive or substantial evidence” for the treatment of chronic pain in adults.

Recognized medical indications for marijuana vary greatly in the United States on a state-by-state basis.

Currently, the U.S. Food and Drug Administration (FDA) doesn’t recognize marijuana for any medical condition.

But certain drugs derived from marijuana, such as Dronabinol (an anti-nausea drug) and Epidiolex (an antiseizure drug) have both received FDA approval.

Critics of the Australian study have also seized on what they say is potentially misleading methodology.

Medical marijuana was only decriminalized in Australia in 2016, meaning that the majority of the study cohort was using and reporting on illegal cannabis use.

“There exists little to no quality control or standardization of the product they’re obtaining,” said Armentano.

Drug policy watchdogs in Australia have similarly refuted the methodology of the study.

The study authors do acknowledge these limitations in their study. In fact, they fully admit, “it’s difficult to completely understand the effects of cannabis on pain in an observational study.”

The possible impacts

The research has apparently met with strong opposition because of the potential damage it could have on Australia’s nascent medical marijuana legislation.

The Sydney Morning Herald, for example, reported that “cannabis’ medical benefits have suffered a serious blow.”

Others have also praised the study, which was described as one of the longest, in-depth prospective studies of chronic noncancer pain and cannabis use.

“This was a very well-designed study,” Otis W. Brawley, chief medical officer of the American Cancer Society, told Healthline. “They wanted to be fair and objective.”

Brawley was impressed by the study’s equipoise and stressed that marijuana prejudice by both pro-marijuana and antimarijuana lobbies has made high quality research of the drug nearly impossible.

“There’s so much prejudice against cannabis that the legitimate scientific studies that should be done haven’t been done. So, you hear a lot of anecdotes about cannabis being used to treat pain, cannabis being used to treat a number of things,” said Brawley.

“I would hope that as time moves on people will actually take a serious objective look at cannabis, the way these authors did,” he said.