A descriptive study of older medical cannabis users in medical cannabis clinics

Introduction There is a dearth of information on older users (65+ years) of medical cannabis, who may face unique challenges due to altered metabolism with aging, concurrent medication use, and risk of adverse effects. This observational study aimed to describe a large cohort of older medical cannabis users in Canada. Methods From Oct 2014 to Oct 2020, a commercial medical cannabis provider based in Canada collected anonymized data for research purposes from patient volunteers. Data included demographic, social, and health details (at intake) and cannabis products, self-perceived changes in symptoms and change in medications (at follow-up, variable duration). Cannabis products were categorized as cannabidiol (CBD) only, tetrahydocannabinol (THC) only or mixed CBD/THC. Of the mixed, formulations could be in 1:1 ratios (CBD+/THC+), predominantly CBD (CBD+/THC-) or predominantly THC (CBD-/THC+). Results In total, 9766 subjects in the older cohort (65+ years old) completed the entire questionnaire (mean age (SD) = 73.6 (6.8) y, 60% female). They represented 23.1% of the total dataset (N = 42,267, mean (SD) =51.5 (16.8) y). The proportion of adults in the older cohort tended to increase over time (pre-2018: 17.6%; 2018: 26.7%; 2019: 31.2%; 2020: 22.7%, when the overall intake decreased from 8869 to 5644). Among the older cohort, 15.5% were previous cannabis users and 67.7% were referred for chronic pain (mainly arthritis, chronic pain, lower back pain). Concomitant analgesic use was common (over-the-counter analgesics: 44.5%; opioids: 28.3%; NSAIDs: 24.5%). 7.9% of the sample (compared to 19.9% in the whole sample) were referred for psychiatric disorders, though 21.4% indicated antidepressant use and 12.3% indicated benzodiazepine use. Another 7% were referred for neurological disorders. Follow-up data were captured in visits (11,992) from 4698 older patients, averaging 2.5 visits per patient. The type of medical cannabis used changed over time, with increasing use of cannabis oil compared to herbal cannabis. In 2020, of 2478 visits, 78.9% use was cannabis oil and 6.7% was herbal forms (pre-2018: 57.6% vs 36.2%). The composition of cannabis oil demonstrated a preference for cannabinoid oil (CBD+) over tetrahydrocannabinol (THC+) in 6043 visits: 45.2% were using CBD+ preparations, only 3.2% were using THC+ preparations, and for CBD/THC combinations, CBD predominated (CBD+/THC-: 30.5%; CBD+/THC+: 16.8%; CBD-/THC+: 4.3%). Adverse-effects (7062 visits) included dry mouth (15.8%), drowsiness (8.6%), dizziness (4%) and hallucinations (0.6%). Patients reported improved pain, sleep and mood over time, though 15-20% reported no improvement or worsening. Medication use was mostly unchanged, though 40% of opioid users reported requiring reduced dosages. Conclusions These data were drawn from a large convenience sample. The data suggest an increasing proportion of older users of medical cannabis, though COVID-19 may have affected recent use. Female users comprised a higher proportion, and cannabis oil containing CBD was preferred. Systematic studies of effectiveness and safety in older users of cannabinoids are needed given its increasing use. Funding No funding was received for this work.