The evolving culture of medical cannabis in Canada for the management of chronic pain

2.1 Timeline for access to medical cannabis in Canada

As Canada has been at the forefront of cannabis legalization, the timeline for access will be examined. Although MC is not a Health Canada approved treatment, legislation has progressively allowed for easier access for patients. Following court rulings based on appeals by patient advocates, Health Canada adopted the Marijuana Medical Access Regulations (MMAR) in 2001 which allowed seriously ill Canadians to obtain authorization to possess dried marijuana for their own medical use with the authorization of a medical practitioner. Certain medical conditions were allowed and included severe pain from severe forms of arthritis, when the medical practitioner stated that “conventional treatment(s) have been tried or considered and have been found to be ineffective or medically inappropriate”. Under these regulations, the medical practitioner provided the medical justification for an application but did not provide a traditional prescription. Approval for possession of a specified amount of herbal cannabis was given by Health Canada through the Medical Marijuana Access Regulations (MMAP) for a period up to 1 year. Once approved, Health Canada arranged for cannabis to be sent directly to the patient (Health Canada, 2010). These initial regulations were eased when Health Canada repealed the MMAR in March 2014 and replaced the MMAR with the “Marijuana for Medical Purposes Regulations” (MMPR) (Government_of_Canada, 2013). Under these regulations the medical practitioner is required to complete a “medical document”, stating the daily dose and duration of use, without restriction for specified medical conditions, and without need to document failure of conventional treatments. This was met with mixed emotions from healthcare practitioners, most of whom resisted or refused any involvement in medical authorization of cannabis, while a small minority embraced cannabis authorization and created clinics often associated with Licensed Producers. Cannabis medical legalization and its evolution over the past decades has promoted the perception of safety compared to traditional drug therapies for many conditions and has influenced uptake of cannabis by adults (Carliner et al., 2017).

3.1 Evidence for effect of cannabis for chronic pain

Clinical evidence needed for widespread acceptance and implementation of a drug for a condition specific indication is accrued via the successful completion of randomized controlled clinical trials (RCTs). This information is lacking for MC due to two barriers: 1) few formulations of plant based medical cannabis extracts in the North American marketplace meet pharmaceutical standards required for Health Canada/Food and Drug Administration (FDA) regulatory approval; 2) the designation of cannabis (in particular THC) as a controlled substance. These barriers have contributed to a paucity of clinical trial literature, especially for management of chronic pain especially of a musculoskeletal nature, with current evidence deemed insufficient to justify use (Fitzcharles et al., 2016). The importance of the placebo effect in studies of cannabis-based therapies for chronic pain has been highlighted by the results of a systematic review and meta-analysis of twenty studies, including 1,459 individuals (Gedin et al., 2022). Pain intensity was significantly reduced in response to placebo, with a moderate to large effect size [mean (SE) Hedges g, 0.64 (0.13); p < 0.001], leading the authors to conclude that placebo contributes significantly to pain reduction, and postulating that positive media attention may have played a role in the drugs acceptance and popularity among patients. Given the absence of clinical evidence, physicians have lacked confidence in their knowledge of cannabis as a therapy and continue to be hesitant to recommend its use (Fitzcharles et al., 2014; Ablin et al., 2016; Rønne et al., 2021; Cheng et al., 2022). In Canada, only about 8% of the 92,173 registered physicians provided medical authorization for MC in 2021, but with considerable differences noted between the various provinces. It is therefore understandable that patients wishing to try MC may choose to seek other avenues of access which often leaves them vulnerable to poor outcomes.

3.2 Increase in self-administration

Cannabis recreational legalization in Canada has opened an avenue for easier access for patients wishing to self-medicate or experiment with use, but often without physician or pharmacist oversight. Patients can thus avoid tensions or conflicts with physicians unwilling to authorize use and by-pass the administrative steps to access MC. Although many obtain cannabis from legal recreational outlets, the more favourable pricing of street cannabis is a necessity for many patients. Since cannabis recreational legalization, only 20% of surveyed Canadian rheumatology patients accessed MC entirely via the legal medical route, with many obtaining cannabis for therapeutic reasons via the illegal recreational route (Fitzcharles et al., 2020). Of concern is that only one-third disclosed their cannabis use to their treating physician. Given this increase in acceptance post legalization and the ease of access, the 2021 Canadian Cannabis survey identified that 25% of Canadians have used cannabis in the last 12 months with the younger demographic (<25) approximately doubling that of 25 and older Canadians (Canadian_Cannabis_Survey, 2021). This pattern of accessing cannabis illegally for medical purposes is seen similarly in other countries. In an anonymous on-line survey of therapeutic cannabis use in Australia, only 2.7% of 1,388 respondents accessed cannabis via the legal medical route and only 5% sought advice about cannabis from a healthcare professional, often relying on personal study, internet-based media or cannabis advocacy groups (Lintzeris et al., 2020). The main perceived barriers to MC use reported in this study were cost, disinterest from the medical profession and stigma. Street cannabis use by patients raises concerns about molecular content of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), quality, additive products, contaminants and the increasing concentrations of THC. Canada has implemented stringent quality control and quality assurance measures for all classes of cannabis to sufficiently inform consumers and to ensure that the cannabis supply is safe (Pusiak et al., 2021). However these regulatory standards fall short compared to tobacco regulations (Moir et al., 2008). We note that mean concentrations of THC in illicit cannabis have steadily increased globally, with levels almost doubling from around 9% in 2,000% to 18% in a period of 5 years as noted in the Netherlands (Mensinga et al., 2006). The THC content of cannabis products offered by on-line dispensaries in the US did not differ between recreational or medical use, and for medical use was on the higher side at about 20% (Cash et al., 2020). Studies of MC to date have examined effects of cannabis with THC content mostly in the order of 9%, with a single study in pain relief using 12.5% THC content (Ware et al., 2015).

3.3 Potential risks associated with medical cannabis

Patients may not be sufficiently aware of risks associated with cannabis, especially when consumed for a health-related condition without supervision. The potential risks can extend beyond the individual and have societal implications such as occurs when persons experience psychomotor effects and are at risk of motor vehicle accidents (Asbridge et al., 2005; Lee et al., 2021). In a study assessing the impact of MC authorization on motor vehicle-related health utilization visits in Ontario, Canada, between 2014 and 2017, Lee et al. reported an increase of 2.92 events/10,000 (95%CI 0.64–5.19) compared to controls over the follow-up period. This effect was largely driven by motor vehicle crash related emergency department visits (+0.80 events/10,000, p < 0.001) (Lee et al., 2021).

The long-term effects of cannabis must be considered, especially for a younger person using MC for treatment of chronic pain, with the potential for a daily lifelong treatment. There is little debate that the daily use of high dose THC products increase the risk of developing a cannabis use disorder. The 3 year incidence of cannabis dependence for frequent cannabis users is reported as 37% (van der Pol et al., 2015). In the coming years, it will be important for data to continue to be collected on the amount of cannabis used, whether higher concentrations of THC is favoured and the incidence of cannabis use disorder for patients using MC in Canada.

3.4 Medical cannabis as a substitute for opioids

Can MC be used as an effective substitute for opioids in persons with chronic pain with less potential for harm? Opioid reduction has been commonly reported in both on-line and observational studies, but with lesser effects observed in the setting of formal controlled trials (Lucas and Walsh, 2017; Abuhasira et al., 2018; Boehnke et al., 2019b; Meng et al., 2021; Noori et al., 2021). Almost half of 2,697 Canadian participants in an on-line survey receiving legal MC reported that cannabis had enabled substitution for other substances (alcohol 18%, tobacco 8%, opioids 18%, other prescription medications 18%) (Holman et al., 2022). An observational study of 757 patients followed at community-based cannabis clinics in Ontario, Canada reported that the proportion of those using opioids decreased by half from 41% to 24% at 12 months (Meng et al., 2021). In a small cohort of chronic pain patients consuming cannabis, the majority (96%) self-reported effective pain management, and 76% reported a significant decrease in analgesic medication usage (Ajrawat et al., 2022). Similarly, over half of participants with rheumatic diseases in a survey of Canadian and US participants reported discontinuation of various medication groups, including opioids as a result of MC substitution (Boehnke et al., 2022). In an on-line survey of over 800 persons with fibromyalgia, 53% reported that cannabidiol (CBD) products allowed them to reduce or even discontinue opioid use (Boehnke et al., 2021).

In contrast to the encouraging reports of opioid reduction in cohort studies, the conclusions of a systematic review and meta-analysis which included five RCTs (patients with cancer-related pain) and 12 observational studies (10 included patients with chronic non-cancer pain) are that the opioid-sparing effects of cannabinoids for chronic pain remains uncertain due to very low certainty evidence (Noori et al., 2021). However, one of the major caveats is that patients included in the RCTs were instructed not to alter their opioid dose, as such the expectation of an opioid reduction seems unrealistic. Non-etheless the authors reported that the addition of cannabinoids resulted in only a trivial difference in cancer-related pain (weighted mean difference (WMD) −0.18 cm; 95%CI −0.38–0.02 on the 10 cm VAS for pain), and very low certainty evidence for opioid reduction among patients with chronic non-cancer pain (WMD −22.5 mg morphine equivalent (MME); 95%CI −43.06–−1.97) (Noori et al., 2021). In 2021, using Delphi methodology, a group of experts proposed a strategy for the safe introduction and titration of cannabinoids in concert with opioid tapering (Sihota et al., 2021).

3.5 Cannabis clinics and dispensaries

As the cannabis industry flourished from 2014—2018, many specialized “cannabis clinics” staffed by healthcare professionals emerged. These clinics were often developed to fill a void in patient care as many physicians may have been unwilling to prescribe cannabinoids either due to lack of confidence in their personal knowledge, concerns about the evidence for effect, or simply personal bias. When functioning only to prescribe cannabis, these clinics represent less than ideal medical care, but did provide a service that should not have been necessary. It is however notable that the primary purpose and raison d’ etre for a cannabis clinic is the authorization of cannabis products for health-related conditions. Some clinics took a wholistic approach, but others were less committed to comprehensive patient care, and were primarily focused on the authorization of cannabis and often associated with particular licenced producers. One-third of patients who responded to an on-line survey and were Canadian federally-authorized cannabis patients received their authorized products from a secondary specialized cannabis care provider, most of whom worked in a clinic that specialized in MC (Holman et al., 2022). Although participants rated their primary care provider as having “good” knowledge of MC and were moderately confident that MC could be integrated into their treatment, higher ratings were given for secondary care providers knowledge about MC, but with 71% of secondary providers not involved in the participants’ medical care other than authorizing MC (Holman et al., 2022).

It is unique and outside the usual paradigm of medical care that a physician should focus on the prescription of a single drug. The Canadian Medical Protective Association, the largest medical insurance liability provider in Canada, has cautioned physicians to only provide a prescription for MC when conventional treatments have failed or are inappropriate, when “they have the necessary clinical knowledge to engage in meaningful consent discussions with patients” and should inform the patient of “the lack of information to date.” (Canadian_Medical_Protective_Association). Even prior to the advent of virtual medicine as a new form of care introduced in early 2020 during the COVID pandemic, many cannabis clinics offered an on-line consultation for the purpose of providing authorization for MC with only superficial knowledge of the patient. Cannabis clinics advertise their services as “experts” in this field which is a misrepresentation to a patient community that requires comprehensive clinical care and not a single magic potion.

Cannabis dispensary staff and licensed producer personnel have become increasingly present in counselling patients on use of MC, often without medical background and therefore at risk of providing inappropriate medical advice (Dickson et al., 2018; Lim and Kirchhof, 2019; Merlin et al., 2021). In a US survey of 434 cannabis dispensary staff, with only 13% identified as pharmacists, advice about MC was given mostly based on the medical condition 74%, experience reported by other customers 70%, and dispensary staff personal experience 63%, but with “clinical input” (not further specified) identified for 40% (Merlin et al., 2021). It is also notable that 64% of respondents held a medical cannabis card. It is encouraging to note that cannabis retail workers who recently participated in a focus group study in Washington State identified their professional roles as being compliant with state law and regulations, did not believe their job involved discussions around pregnancy or driving, and educated consumers on how to avoid over intoxication (Carlini et al., 2022). On-line information on MC, especially from dispensaries reflects positive attitudes and beliefs that could be misleading for patients. Cannabis dispensaries are not altruistic health focussed endeavours, but commercial enterprises with the objective of achieving profit by sale. It is therefore not surprising that patients report satisfaction with dispensary interaction (Capler et al., 2017). Furthermore, the greater availability of cannabis dispensaries may be a risk for adverse effects on health, with increasing cannabis dispensary density associated with more hospitalizations for cannabis use disorder in California (Mair et al., 2021). It is encouraging to note that a 2021 survey of dispensary staff in Canada mostly advised against use of MC in pregnancy (Vastis et al., 2021).

The existence of cannabis clinics is dependent on the continued use of MC by those attending. We express concerns that patients may not be receiving the best care for their chronic pain management if the dispensary or the cannabis clinic is their primary pain care provider. Patients should not be receiving medical advice from dispensary staff, with the exception of qualified pharmacists who may be working in a dispensary. We acknowledge that there will be patients who experience symptom relief with use of MC, but this treatment should be a component of a multidisciplinary care model, including non-pharmacologic, as well as other pharmacologic treatments.

4.1 Patient reported symptom relief

Chronic pain is the most common reason for Canadian patients to use MC (Walsh et al., 2013; Banerjee and McCormack, 2019; Fitzcharles et al., 2020; Meng et al., 2021). Patients’ dissatisfaction with drug treatments that are either often only modestly effective or associated with unacceptable side effects is an important driver of consideration of MC (Kosiba et al., 2019). Between 30% and 80% persons cite musculoskeletal painful symptoms as reason for MC use (Ware et al., 2005a; Swift et al., 2005; Aggarwal et al., 2009). Pain relief is also cited by patients in the US (Zaller et al., 2015; Boehnke et al., 2016; Piper et al., 2017a), United Kingdom (Ware et al., 2005b), and Australia (Swift et al., 2005) as a reason for MC use. The increased prevalence of pain in the elderly is contributing to MC use in this age group. In a survey of 470 persons over 60 years age in Colorado and Illinois, recruited via senior centres, health clinics and university research volunteer lists in 2017–18, almost half used some pain relieving treatment in past year with opioid use by 13%, cannabinoid use by 15%, and use of both by 15% (Bobitt et al., 2020).

Pain relief is generally reported to be substantial with use of MC (Meng et al., 2021). Numerous observational studies in various countries have reported patient satisfaction with MC for chronic pain management, including as a substitute for opioids and other pain medications (Boehnke et al., 2016; Piper et al., 2017b; Corroon et al., 2017; Boehnke et al., 2019b; Boehnke et al., 2021; Meng et al., 2021). Beyond only pain relief, surveys also report effect on sleep disturbance, although these effects have not been confirmed by randomised clinical trials (Harris et al., 2000; Nunberg et al., 2011; Ilgen et al., 2013; Walsh et al., 2013; Grella et al., 2014; Zaller et al., 2015; Lucas and Walsh, 2017; Abuhasira et al., 2018). An online survey of almost 1,000 patient members of MC dispensaries in New England rated symptom relief as 75%, with options between 0% “no relief” and 100% “complete relief” (Piper et al., 2017a). Although the numbers of patients trying MC has increased in recent years, the numbers that continue to use remain consistent at about 50% (Fitzcharles et al., 2020; Boehnke et al., 2022).

Adherence to a specific treatment over time can be seen as a surrogate for perceived efficacy. Validated real-world information about the continuation of use of MC and effect on use of other prescribed or over-the-counter medication is urgently needed. Many studies reporting favourable effects may be subject to bias due to convenience sampling or study setting in cannabis clinics or cannabis dispensary driven data. Compliance and success with use may be better when a patient is followed by a qualified healthcare professional, with guidance about products and dosing, such as reported by clinics in Israel (Abuhasira et al., 2018).

5.1 Current Canadian cannabis market

The current cannabis market has influenced patient use of MC. MC is costly, rarely reimbursed and constitutes a considerable financial burden for patients leading some to turn to the recreational or street market. Canada has seen a progressive growth in the legal recreational market, an overproduction of cannabis and a contraction of the MC market, which now makes up only about 6% of total cannabis sales (Cannabis_market_data, 2022). In this climate of overproduction and intense competition with the illegal cannabis market, there has been a progressive reduction in price of both the legal and illegal recreational product in Canada (Stratcan, 2021; Mjbizdaily, 2022). Therefore, easier access and reduced cost are factors leading patients away from the medical route and leading to more self-administration. Another healthcare consideration being brought to the forefront is that legal medical or recreational cannabis is not regulated to the same standard as approved drugs or tobacco products. The inaccuracies of molecular concentrations on cannabis products (Oldfield et al., 2021) and contamination with levels of mold, ammonia, etc., in products being consumed in the marketplace have raised questions about lax standards at the regulatory level (Moir et al., 2008).

The increased availability of cannabis has allowed patients to bypass interaction with their healthcare provider and to self-administer. Healthcare oversight is critical when a product is used as a therapy. Patients have reported that their own personal belief in MC and physician input influences choice, with the odds of choosing MC increased 24–43 times if the physician had talked about cannabis (Bobitt et al., 2020).

The authors wish to thank Professor François Vaillancourt, emeritus professor, sciences économiques, Université de Montréal for careful reading of the manuscript and input regarding socioeconomic issues.