Cannabis Use Appears to Encourage, Not Replace, Opioid Use, Study Claims
Contrary to previous research on the topic, a new study from researchers at Columbia University has found that cannabis may not curtail illicit opioid use after all.
Published in Addiction, the study assessed the strength of association between self-reported cannabis and opioid use over a period of 90 consecutive days, finding that opioid use was at least as prevalent, if not more so, on days when participants also used cannabis.
This association did not appear to be impacted by self-reported pain levels, suggesting that cannabis is not actively being used as a substitute for opioids.
A more frequent assessment
There is a mixed scientific evidence supporting the idea that cannabis is being substituted in for opioids among certain individuals, particularly among those looking to manage pain.
Physically, it has been shown that cannabis is able to activate similar neurological pathways as opioids, and so might potentially provide similar relief from pain or cravings. Observational studies have also indicated that this substitution is relatively common among authorized medical cannabis patients.
However, two major longitudinal studies directly contradict those findings. In these studies, cannabis use actually appeared to increase the risk of using non-medical opioids. Although due to the design of the studies, cannabis and opioid use figures were only measured at two distant time-points.
In a bid to provide clarity, the authors of the new research examined any associations between cannabis and opioid use over 90 days, with measurements taken daily.
Substitution is unlikely, even with significant pain
Participants in this study came from a wider study on substance use disorders and were recruited from the local community and from a suburban inpatient addiction program, with the general demographic spread being similar to that of medical cannabis users.
Eligible participants – those who reported using opioids for non-medical purposes within the past month – were then asked to call or text an interactive voice response system each day to answer questions on their health and substance use the previous day.
Using the data gathered from these daily questionnaires, the researchers found that, on average, participants reported using opioids without cannabis on 15 percent of the days, cannabis without opioids on a further 15 percent of days, and both substances on 7 percent of days.
Most notably, it was discovered that the odds of using opioids actually nearly doubled on days where cannabis was used. The strength of this relationship was not significantly altered by the presence or absence of moderate-to-severe pain, the severity of any opioid use disorder, or by gender.
“Our results suggest that cannabis seldom serves as a substitute for non-medical opioids among opioid-using adults, even among those who report experiencing moderate or more severe pain,” Deborah Hasin, professor of epidemiology at Columbia Mailman School of Public Health, said in a statement. “In other words, our study suggests that cannabis is not an effective way to limit non-medical opioid use.”
Why does an association between cannabis and opioid use matter?
The design of this study makes it among the first to directly test for opioid substitution and suggests that cannabis seldom serves as a substitute for non-medical opioids. But why does this association need to be studied at all?
On average, 41 people die each day in the United States from overdoses involving prescription opioids. The number of opioid-related deaths is so extreme that in 2017 the acting health and human services secretary declared the opioid crisis an official public health emergency. While interventions such as increasing treatment services and prescription drug monitoring problems have worked to decrease this death rate in recent years, there is still a need to develop other ways of addressing this crisis.
One of these novel policy ideas is the legalization of medical cannabis. The general notion is that if cannabis can be effectively substituted for opioids, then it should be possible for people with opioid use disorders to transition to medical cannabis, which would act as a safer, less-addictive alternative.
Indeed, some states already list opioid addiction as a valid qualifying condition for accessing a medical cannabis prescription. Perhaps spurred on by this, a significant proportion of medical marijuana dispensaries are also already making “unsupported claims” implying that cannabis can effectively treat opioid use disorder, despite the current mixed state of scientific evidence. Highlighted in a recent JAMA Network Open study, these claims were also found to appear more frequently in those states which list opioid use disorder as a qualifying condition.
As the current study demonstrates, more research into the exact nature of the relationship between cannabis and opioid use is sorely needed. Fully understanding how the plant might alter non-medical opioid use should be a critical component in informing ongoing discussions on cannabis-related interventions for combatting the US opioid crisis.
