Medical Cannabis Use Among Older Adults in Canada: Self-Reported Data on Types and Amount Used, and Perceived Effects

Drugs & Aging https://doi.org/10.1007/s40266-021-00913-y ORIGINAL RESEARCH ARTICLE Medical Cannabis Use Among Older Adults in Canada: Self‑Reported Data on Types and Amount Used, and Perceived Effects Shankar Tumati1 · Krista L. Lanctôt1,2,3 · RuoDing Wang1 · Abby Li1 · Andrew Davis4 · Nathan Herrmann1,2 Accepted: 2 December 2021 © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021 Abstract Background Medical cannabis use is growing among older adults. In this retrospective study, we aimed to assess the characteristics of older medical cannabis users including the indications, type and amount of cannabis used, perceived changes in symptoms after cannabis use, change in dose of concurrent medications, and adverse effects. Methods Data were collected between October 2014 and October 2020 from patients who were consulting the Canada-wide network of clinics of a medical cannabis provider and who were willing to answer questionnaires based on their medical status. The current study included older adults (≥ 65 years) who completed questionnaires at intake and first follow-up visits. Data were summarized with descriptive statistics, which were compared between men and women with t tests or chi-squared tests. Tests of proportions assessed categorical responses for perceived effects after cannabis use. Logistic regression was used to assess trends in cannabis usage. Results Data included that from 9766 older adult users at intake (mean ± SD age = 73.2 ± 6.8 years, females = 60.0%), among whom 4673 (females = 61.4%) returned for follow-up after 90.6 ± 58 days. The most common primary indication for which medical cannabis was sought was pain (67.7%), which was more common in women, whereas oncological and neurological conditions were more common in men. At follow-up, cannabis oil was used by 81.0% of older adults, among whom compositions containing only or mostly cannabidiol (CBD) had been used by 83.6%. Adverse effects reported by older adults at the follow-up visit included dry mouth (12.8%), drowsiness (8.6%), and dizziness (4.0%). The majority of older adults reported improvements in pain (72.7%, z = 1482.6, p < 0.0001, compared to worsening or no change), sleep (64.5%, z = 549.4, p < 0.0001), and mood (52.8%, z = 16.4, p < 0.0001), with 35.6% reporting use of a reduced dose of opioids and 19.9% a reduced dose of benzodiazepines. Interpretation Among older adults, medical cannabis is used more often by women, with CBD-containing cannabis oils being the most commonly used. Users reported improved pain, sleep, and mood symptoms at follow-up after cannabis use. This study describes the patterns of use of medical cannabis by older adults and highlights the need for research to determine appropriate indications, precise doses of active ingredients, and short- and long-term outcomes among older adults. Key Points * Krista L. Lanctôt 1 Neuropsychopharmacology Research Group, Sunnybrook Research Institute, Toronto, ON, Canada 2 Department of Psychiatry, University of Toronto, Toronto, ON, Canada 3 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada 4 Department of Economics, Acadia University, Wolfville, NS, Canada Older adults used medical cannabis most often for pain, and use was more common among women. The most commonly used form was cannabis oil; most users consumed < 2 ml/day and favoured compositions containing mostly or almost exclusively cannabidiol. A majority of older adults reported improvement in pain, sleep, and mood after medical cannabis use. Vol.:(0123456789) S. Tumati et al. 1 Introduction Cannabis has been used globally for medical and nonmedical purposes [1]. In the 20th century, several countries prohibited cannabis use due to concerns over its abuse potential [2]. However, attitudes towards cannabis have shifted over the last 3 decades possibly due to the perceived benefits for health problems, the challenges faced by the legal system in reducing use, and the costs of implementing prohibitory laws [3]. Canada has been at the forefront of these developments [4] and was among the first countries in the world to develop a legal and regulatory framework for therapeutic cannabis use by severely ill patients [5]. Under that framework, medical cannabis was accessed by over 300,000 patients in 2020 [6]. Moreover, in 2012, despite being illegal at that time, 42.5% of Canadians reported using cannabis at least once over their lifetime [7]. The high rates of cannabis use combined with a shift in public opinion led to the legalization of nonmedical cannabis use in 2018 in Canada [8, 9]. National Canadian surveys estimate that the percentage of those using cannabis in the past year grew from 9.4% in 2004 to 14.0% in 2014, and further from 17.5% in 2019 (past 3 months use, post-legalization) to 20.0% (past 3 months use) in 2020 [10]. Over that period, adults aged 65 years and above were the fastest growing user age group [11–13], increasing from 0.8% in 2012 [7] to 6.6% in 2019, including 27.0% first-time (past 3 months) users [13]. A similar increase in older cannabis users has been reported in other countries [14–16]. While men use cannabis more often, rates of cannabis use among women have increased in recent years [10, 17]. Despite the increasing number of publications on medical cannabis [18], there is a dearth of information about its use among older adults. For example, surveys by Health Canada provide aggregate data for all adults aged 25 years and above [5, 17]. Consequently, older adults who are more likely to source cannabis legally, rely on non-clinical sources to guide cannabis use [19–21]. At the same time, physicians report concerns about cannabis use among older adults due to a lack of evidence for benefits and harms [22]. As such, Canadian clinical practice guidelines recommend restricted use of synthetic cannabinoids (e.g., nabilone and nabiximols) only for neuropathic pain, palliative care, nausea and vomiting associated with chemotherapy, and spasticity due to multiple sclerosis or spinal cord injury, while recommending against cannabinoids for other conditions [23]. Notably, no age-specific recommendations are provided. Older adults use cannabis for medical conditions more often than young and middle-aged adults [24, 25], with more than half (52.0%) reporting medical use exclusively, and an additional 23.6% reporting cannabis use for medical and non-medical purposes [13]. These conditions include chronic pain due to musculoskeletal disorders and cancer, chemotherapy-associated nausea, vomiting and loss of appetite, and various neurological and inflammatory conditions [26, 27]. Cannabis has also been used for mental health conditions such as anxiety, depressive symptoms, insomnia, and post-traumatic stress disorder [14, 27]. Among older adults, adverse events, which include dizziness, dry mouth, somnolence, and falls, are of concern [28, 29] and may be more related to tetrah (...truncated)