Canadian cannabis study finds long-term use does not increase pain sensitivity


A recent study looking at pain among cannabis users has found that regular cannabis use doesn’t appear to increase pain sensitivity – unlike long-term opioid use.

The study, done by doctoral student Michelle St. Pierre in the psychology department of the University of British Columbia, Okanagan, looked for differences in pain tolerance in those who regularly use cannabis and those who do not. The study was published in the Clinical Journal of Pain.

“Recent years have seen an increase in the adoption of cannabinoid medicines, which have demonstrated effectiveness for the treatment of chronic pain,” St. Pierre said. “However, the extent to which frequent cannabis use influences sensitivity to acute pain has not been systematically examined.”

Recent surveys of medical cannabis patients have found that more than half of the patients used cannabis for pain relief, despite some indication that its effectiveness in treating chronic pain is mixed.

“This study should come as good news to patients who are already using cannabis to treat pain,” said co-author Zach Walsh, who leads the UBC Therapeutic Recreational and Problematic Substance Use Lab, which hosted the study. “Increases in pain sensitivity with opioids can really complicate an already tough situation; given increasing uptake of cannabis-based pain medications, it’s a relief that we didn’t identify a similar pattern with cannabinoids.”

For the study, St. Pierre recruited volunteers who used cannabis more than three times per week, as well as volunteers who didn’t use it at all. Participants were asked to submerge one of their hands up to the forearm into icy water for a sustained amount of time. From the tests, she determined that cannabis use does not increase hyperalgesia that is seen in opioid use.

“Our results suggest frequent cannabis use did not seem to be associated with elevated sensitivity to experimental pain in a manner that can occur in opioid therapy,” she says. “This is an important distinction that care providers and patients should consider when selecting options for pain management. These findings are particularly relevant in light of recent reports of opioid overprescribing and high rates of pain in the population, as it suggests that cannabis may not carry the same risk of hyperalgesia as opioids.”