By now, the statistics about the opioid crisis in North America are well known. Many of us are familiar with the impacts of opioid prescription use and abuse. After more than a decade of headlines, the crisis continues its slow and steady crawl across society, seemingly without an end in sight.
As a reminder, in 2018, there were 4,588 deaths in Canada related to the opioid epidemic. That’s one death every two hours. And the rising trend was continuing into the early months of 2019. In the US in 2017, according to statistics compiled by CNN, there were 47,600 opioid-related deaths, which accounted for close to 70 percent of all overdose deaths in the country.
Approximately 1.7 million Americans have a prescription opioid substance abuse disorder. Despite recent court cases and settlements with the companies behind these pharmaceuticals, North America is by no means through the pandemic. If anything, the numbers suggest we are still in the thick of things.
While opioid prescriptions and addictions were on the rise in North America, the continent has also been experiencing a wave of cannabis legalization. Starting in the early 2000s with several progressive states, medical cannabis is now normalized in the US and Canada. Today, more states than not have approved medical cannabis use, while increasing numbers (and Canada) support recreational adult use.
A Complicated Correlation: Cannabis and Opioids
It’s an interesting parallel between rising opioid abuse and increasing access to medical cannabis. These trends have not gone unnoticed, especially as both opioids and cannabis are options for the treatment of chronic pain. But what impact has increased cannabis access had on opioid abuse?
As a plant-medicine, cannabis has many valuable qualities, especially as an alternative or cotreatment with prescription painkillers. Older ecological studies have strongly suggested cannabis legalization reduces the regional reliance on and abuse of opioids—yet, new research has thrown this conclusion into question.
The 2014 population survey, which was originally responsible for the wave of excitement about cannabis’ impact on opioids, was published in the Journal of American Medical Association of Internal Medicine. In the study, the authors examined populations in the US exposed to medical cannabis, and the outcomes of this exposure. They pulled data from 1999 to 2010, using time series analysis of state death certificates and medical cannabis laws.
The reason why their research made national headlines was because it strongly suggested that once a population had legal access to medical cannabis, it then had lower opioid mortality rates. Results were more than just measurable; they were substantial. Overall, the report found a 24.8 percent lower mean annual opioid overdose mortality rate when medical cannabis was legal and accessible.
It’s been close to a decade since the authors pulled the population data on this subject, and the legal landscape has drastically changed. By the end of 2010, a total of 13 states had medical cannabis. Today there are more than 30, not to mention the wave of recreational reform. Strangely, especially with the 2014 survey in mind, opioid deaths and substance abuse disorders continue to rise over this same period, contradicting the correlation of the 2014 study.
New research, published through the National Academies of Sciences in 2019, found that the previous relationship between cannabis and opioid mortality has reversed in the subsequent nine years after the original study concluded.
This new research shows that while access to medical cannabis has increased, so too have opioid-related deaths in the US, despite the fact the new study relied on the same methods as the original research. The authors of this new and improved population analysis did not mince words when they said, “We find it unlikely that medical cannabis—used by about 2.5% of the US population—has exerted large conflicting effects on opioid overdose mortality.”
But, as a lead author, Chelsea Shover explained to STAT, “This isn’t to say that cannabis was saving lives 10 years ago and it’s killing people today. We’re saying these two things are probably not causally related.” Although the original ideas about cannabis’ impact on opioids may have been spurious, it doesn’t mean there is no place for cannabis in the treatment of chronic pain.
In Shover’s opinion, there is still immense value in the study of cannabis for pain. Especially if taken down to the individual level, there is still an interesting and potentially useful relationship between cannabis and opioid dependency. Population study is just not the right method to find true causation between these two trends.
Real Impact Only Visible at the Patient Level
At the patient level, the evidence strongly supports cannabis for difficult to treat pain. There is also support for cannabis as a replacement for opioids and other prescriptions. In Cannabis and Cannabinoid Research, authors Keith Humphreys and Richard Saitz found that “[t]hirty-four percent of the sample reported using opioid-based pain medication in the past 6 months. Respondents overwhelmingly reported that cannabis provided relief on par with their other medications, but without the unwanted side effects.”
A 2017 patient survey, this time pulled from Tilray’s customer base found 63% of respondents used cannabis as replacement therapy for prescription drugs. Within that percentage, a full 30 percent reported using cannabis instead of opioid prescription. Both of these publications found pain as the top reason for medical cannabis use.
Emerging research tells us that cannabis coadministered with opioids creates analgesic synergy. In both clinical and preclinical work, the individual pain-relieving value of THC or opiates is no match for when these compounds are used together. Why is this important for the opioid crisis?
According to another paper from the Journal of Cannabis and Cannabinoid Research, a combination strategy “could have significant impacts on the opioid epidemic, given that it could entirely prevent two of the hallmarks of opioid misuse: dose escalation and physical dependence.”
It’s when we drill down to the patient level, that we see the positive impact of medical cannabis on pain relief, and for its potential to reduce prescription opioid use. At the national-stratospheric level, other factors are at play. These factors have dramatically changed previous assumptions about the causation between medical cannabis and opioid abuse.
Time Will Tell How Cannabis Truly Impacts Opioid Use and Abuse
Although cannabis might not solve the opioid crisis, it can still have a role to play for patients suffering from chronic and difficult to treat pain. Once a fringe medicine, cannabis is creeping into our collective medical psyche as a viable solution for certain conditions. With more patients, and more physicians comfortable with cannabis, it could reduce prescriptions with problematic safety profiles, like opioids.
In another five to ten years, we could once again see changes in the trends. Many factors are merging to move cannabis into the mainstream of therapeutic options for pain relief. These factors include clinical studies into cannabinoids for pain relief, a move away from high opioid prescription rates, possible changes in drug scheduling in the US, and greater social acceptance of cannabis. Together, these will combine to make cannabis more accessible and acceptable to patients than conventional prescription opioids. Given a choice, most patients have made it clear they prefer cannabis to opioids.