A Canadian study of patients seeking medical cannabis to treat chronic pain found that almost half stopped opioid use

A study was recently published in a 2021 edition of Canadian Journal of Anaesthesia that investigated patients seeking relief from chronic pain, and who were enrolled in community-based clinics in Ontario between the fall of 2015 and the summer of 2018. Of the patients in the observational study, 62 per cent were female, and 88 per cent reported experiencing chronic pain.

Patients responded to questionnaires and researchers assessed general health symptoms, neuropathic pain, self-reported opioid consumption and adverse events, anxiety, depression and quality of life. The researchers collected demographic information and took these primary factors into consideration while developing a fuller profile of their subjects: pain intensity and pain-related interference scores at baseline and three, six and 12 months. Of the 757 people at baseline, that number dropped to 230 at six months and 104 at 12 months.

Researchers reported results that of the 1,000 patients, 757 (76%) participated at one or more of the study time points. At six and 12 months, 230 (30.4%) and 104 (13.7%) of participants were followed up. Most participants were female (62%) and sought cannabis for pain relief (88%). 

The published study reported that time was a “significant factor associated with improvement in pain intensity, pain-related interference scores, quality of life and general health symptoms.” The article pointed out that the “significant challenges to collecting long-term observational data on patients who attempted a trial of cannabis products.” However, one third of the patients studied continued with medical cannabis for six months, thus reducing pain intensity and pain-related interference that effects quality of life and general health. The proportion of individuals who reported using opioids decreased by half, from 40.8% at baseline to 23.9% at 12 months.

Detailed in a blog published on the website of the American National Organization for the Reform of Marijuana Laws (NORML), results such as these are consistent with other studies. They also noted many study participants switched from consuming herbal cannabis to ingesting oil extracts. Furthermore notes the blog: “Beneficial effects of cannabis appear to persist long-term and tolerance may not become a significant issue for patients on a stable regimen.” 

NORML deputy director Paul Armentano concedes that he believes the results are persuasive. “For many pain patients, cannabis offers a viable alternative to opioids, potentially improving their quality of life while possessing a superior safety profile.”


Canadian Journal of Anesthesia/Journal canadien d’anesthésie (2021)
Blog: NORML, National Organization for the Reform of Marijuana Laws


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