Two new research studies on cannabis and opioid use go public today and their headlines seem to conflict, but actually, these are the principal findings:

Cannabis reduces illicit opioid use among people with chronic pain

and

Cannabis may not be a replacement drug for people with opioid use disorder in methadone treatment

Here we go.

Cannabis reduces illicit opioid use among people with chronic pain

New hope for people using illicit opioids to help with chronic pain comes from the BC Centre on Substance Use (BCCSU) and University of British Columbia (UBC). This research says cannabis may be a beneficial, safer alternative to opioids for some patients.

The team interviewed over 1,100 people at highest risk of opioid overdose over the course of three years. These people reported both major or chronic pain and use of various substances, including cannabis.

The team found a connection between daily cannabis use and significantly lower odds of daily illicit opioid use. This seems to indicate that this subset of patients is successfully managing chronic pain with cannabis, replacing opioids.

“These findings, in combination with past research, again demonstrate that people are using cannabis to help manage many different conditions, including pain. And in some cases, they’re using cannabis in place of opioids,” senior author and research scientist Dr. M-J Milloy said in a press release. “In the midst of an ongoing public health emergency caused by opioid overdose deaths, the results suggest that increasing access to cannabis for therapeutic purposes could help curb overdose risk associated with illicit opioid use.”

Substituting cannabis for opioid meds

Using a statistical model, the team showed that the odds of daily cannabis users using illicit opioids every day were nearly 50 percent lower compared to cannabis non-users. Interestingly, occasional cannabis users were neither more nor less likely to use illicit opioids every day than non-users.

The team also found that daily or more frequent cannabis use may have an intentional therapeutic element folded into it. For example, compared to occasional cannabis users, daily cannabis users were significantly more likely to report various therapeutic uses, including using cannabis to manage cancer or HIV symptoms or drug side effects, mental health, nausea, pain, sleep trouble, and stress.

In other words, some people who experience chronic pain and use drugs may also be using cannabis as a kind of personal strategy to reduce their own opioid use.

“These findings point to a need to design formal clinical evaluations of cannabis-based strategies for pain management, opioid use disorder treatment supports, and wider harm reduction initiatives,” study lead author and public health PhD candidate Stephanie Lake said in the press release. The researchers are planning controlled trials now.

Cannabis may not be a replacement drug for people with opioid use disorder in methadone treatment

Some have considered cannabis as a replacement drug for people with opioid use disorder. However, new research from McMaster University suggests that strategy might not be viable—at least not within the context of methadone maintenance therapy.

The team in this case conducted a meta-analysis of research on the effects of cannabis use on illicit opioid use during methadone maintenance therapy. They found six studies involving more than 3,600 participants.

In the press release, it says that the meta-analysis found that cannabis use did neither reduced illicit opioid use during treatment nor retained people in treatment. There is no further explanation of that conclusion in the press release.

However, here are the conclusions from the study, verbatim:

“Owing to high heterogeneity, we described the studies qualitatively but provide the forest plots as supplemental material. The overall quality of evidence was very low, with a high risk of bias, owing to the nature of observational studies.”

And

We found no consensus among studies that cannabis use is associated with reduced opioid use or longer treatment retention when used during methadone maintenance therapy in patients with opioid use disorder [emphasis added].”

In other words, they did not prove cannabis to be ineffective, or that there is no connection here, even within the limited fact pattern they used. They found that other researchers didn’t agree.

Breaking down results

The researchers have criticized the quality of evidence in other studies—although no other evidence exists—and provided no evidence themselves backing up those conclusions.

It is certainly true that there is a lack of consensus in the evidence that exists. However, this is the statement in the press release from the lead researcher:

“There is limited evidence that cannabis use may reduce opioid use in pain management, and some high-profile organizations have suggested cannabis is an ‘exit drug’ for illicit opioid use, but we found no evidence to suggest cannabis helps patients with opioid use disorder stop using opioids,” senior author and psychiatrist Dr. Zainab Samaan said in the press release.

Neither this statement nor the study seem to reflect what was there, or merit this sensational headline and press coverage they are already receiving.

Conflicting findings on cannabis and opioid use?

Why in the same day can we see these two headlines, both in press releases from Canadian research teams?

“Daily cannabis use lowers odds of using illicit opioids among people who have chronic pain”

and

“Cannabis found not to be a substitute for opioids”

In this journalist’s opinion, the first headline is much more specific. It doesn’t say cannabis is generally a substitute for opioids, for example. It just says daily use lowers odds of illicit opioid use among those with chronic pain—and that’s exactly what the study found.

The second headline fails to reflect the actual findings. Those were that cannabis is not a replacement drug for people with opioid use disorder in methadone treatment—as I wrote above. That is far more specific. If you don’t believe me, here’s the study itself.

We see this repeatedly in our vertical, because vaping is controversial. For example, recently we reported on studies that found vaping damaging to the heart. We also reported on studies that found vaping instead of smoking improves heart health.

The second study got little to no traffic in the press here in the US. The others got a lot, despite their flaws (see our report to learn what they are).

Careful language

Furthermore, the press release and study both cite methadone maintenance therapy as “a common treatment for opioid use disorder.” However, this is somewhat misleading.

In fact, according to the National Institute on Drug Abuse, less than half of privately-funded substance use disorder treatment programs offer this kind of treatment, and only about one-third of opioid use disorder patients in these programs actually receive it.

In other words: they are not looking at the majority of people with opioid use disorder, but are making broader generalizations about the problem anyway.

This is critical research and should not be dismissed or overlooked. There may be no role for cannabis in helping people with opioid use disorder kick their habits in a clinical setting.

However, the headline is misleading, full stop. These are not conflicting findings. This is a public service message from your friends at VV.