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Attitudes to cannabis and patterns of use among Canadians with multiple sclerosis
Multiple Sclerosis and Related Disorders, November 2016, Pages 123 - 126
Canada has the highest incidence of MS worldwide. Anecdotal evidence reveals that people with MS smoke, ingest or vaporize cannabis for a multiplicity of reasons. With the legal situation in relation to use currently in flux, we undertook a study investigating patterns of use amongst people with MS and their attitudes towards the drug.
A consecutive sample of people with MS (n=246) attending a neurology (n=118) and a neuropsychiatry (n=107) clinic was enrolled and asked to complete a questionnaire containing demographic, disease and cannabis related variables.
Of the 246 people approached, 225 (91.8%) agreed to participant. Attitude towards cannabis revealed that 122 (54.3%) participants approved of the drug while 75 (33.2%) were neutral. Legalization was endorsed by 98 (43.7%) participants, while 98 (43.7%) were in favour of legalization for medical use only. Current use was endorsed by 44 (19.5%) people with 125 (56.1%) reporting lifetime use. If cannabis were legal, 113 (50.2%) participants would use it. The most common symptoms for which cannabis was being used were: sleep (86%), pain (75%), anxiety (73%) and spasticity (68%). Participants attending the neuropsychiatry clinic were more likely to use cannabis for managing depression (χ2=4.99; p=0.03) and pain (χ2=3.85; p=0.05).
There is a wide acceptance of cannabis within the MS patient community. One in five people currently use the drug for reasons that differ between neuropsychiatry and neurology clinics. Use could potentially more than double if the drug were legalized.
- 91.8% of people approached agreed to participate in the survey.
- 54.3% of participants approved of cannabis use, while 33.2% remained neutral.
- 19.5% of participants use cannabis.
- 50.2% of the remaining participants would use it if the drug were legal.
- Participants attending the neuropsychiatry clinic were more likely to use cannabis for managing depression (χ2=4.99; p=0.03) and pain (χ2=3.85; p=0.05).
Keywords: Multiple sclerosis, Cannabis, Survey, Neurology, Psychiatry, Cannabis use.
Trying to make sense of cannabis use in people with multiple sclerosis can prove challenging. Multiple variables are at play simultaneously: pharmacologically manufactured versus naturally grown; tetrahydrocannabinol (THC) versus cannabidiol; legal versus illegal to mention but three factors that can determine how the drug is used. What is known is that 14–18% of people with MS report using (inhaling or ingesting) cannabis regularly (Chong et al., 2006) and that 71–94.5% of patients would use the drug if it were legalized (Martínez-Rodríguez et al., 2008). The reasons for use include managing pain, spasticity, emotional dysfunction and insomnia (Clark et al., 2004). These figures should be viewed alongside the recent findings of an American Academy of Neurology task force which found that pharmacologically manufactured cannabis was effective in reducing spasticity, pain and bladder dysfunction, but that there was no comparable evidence for smoked, vaporized or ingested cannabis (Koppel at al., 2014).
Empirical data may not, however, dissuade a person with MS from smoking cannabis in search of symptom relief. Furthermore, legal constraints within Canada are shifting with the drug now more easily obtained through cannabis clinics and politicians from the prime minster down expressing support for legalization (Federal marijuana legislation to be introduced in spring, 2016). With the political situation in flux and with studies describing patients' attitudes to the drug almost a decade old, we decided to revisit the question of how people with MS view cannabis.
Sample selection: Over a three-month period, a consecutive sample of 246 people with MS attending two clinics (neurology and neuropsychiatry) was approached to participate. All subjects had a confirmed diagnosis of MS (McDonald et al., 2001). The only exclusion criterion was intellectual disability.
All subjects were given a questionnaire containing yes/no questions broken down into three categories:
- A. Demographic and MS data age, sex, marital status, employment type, and highest level of education achieved, disease type, length of diagnosis and degree of physical disability. The latter was ascertained with the Patient Determined Disease Steps (PDDS) (Hohol et al., 1999) which focuses on walking ability and consists of patients selecting one of nine descriptions that range from 0 (Normal) to 8 (Bedridden).
- B. Details of cannabis use: Subjects were asked if they had ever used non-pharmacologic cannabis and whether they used it currently. If the response to current use was yes, they were asked about their method, frequency, duration, and cost of use together with their reasons for using. A list of symptoms was provided in relation to the latter.
- C. Attitudes toward cannabis: Subjects were asked their opinion of cannabis relative to other drugs, their beliefs about the benefits and risks of cannabis use, and how they viewed the drug in social and moral contexts.
Ethics: Informed consent was obtained from all participants. The study was approved by the Research Ethics Board at Sunnybrook Health Sciences Centre, affiliated with the University of Toronto. Data were collected anonymously in keeping with the REB requirements.
Of 246 people approached 225 (91.8%) agreed to complete the survey. Reasons for refusal were time constrains (n=6), language barrier (n=5) and unknown (n=9). Of the 225, 118 attended a neurology clinic and 107 attended a neuropsychiatric clinic.
- A. Demographic and neurological data on the participants are given in Table 1.
- B. Cannabis use: Lifetime cannabis use was reported by 125 (56.1%) of people with MS while 44 (19.5%) endorsed current use. Amongst current users, 18 (40.9%) had a prescription from a cannabis clinic and 8 (18.1%) obtained their cannabis directly from the provincial government. Smoking was the most common method of use (n=26; 59.1%), followed by oral ingestion (n=5; 11.4%), vaporizing (n=4; 8.5%) and multiple methods (n=9; 20.5%). Amongst current users, 30 (68.1%) subjects began their use before their diagnosis of MS with 22 (50.0%) subjects reporting having used it for more than 10 years. Frequency of use was as follows: multiple times per day (n=4), daily (n=18), weekly (n=14) and monthly (n=8). In terms of financial costs, 18 (41.0%) subjects reported spending $100–$500 per month on cannabis.
- C. Factors associated with cannabis use. Age: Participants under 40 years of age were more likely than older participants to view cannabis as safer than tobacco (χ2=7.00, p=0.030). There were also trends towards participants under 40 seeing cannabis as safer than alcohol (χ2=4.86, p=0.088), and being less likely to say they would be uncomfortable with people around them using cannabis (χ2=4.05, p=0.058). Gender: Men were significantly more likely to report currently using cannabis (χ2=7.73, p=0.007), to view cannabis as being safer than alcohol (χ2=6.08, p=0.048), and to say they would accept a “puff” of cannabis from a friend or family member (χ2=5.86, p=0.023). There were trends for men rather than women to have used cannabis long-term (χ2=7.23, p=0.065) and to have ever used cannabis (χ2=3.49, p=0.065). Men were less likely to endorse feeling uncomfortable with people around them using cannabis (χ2=5.15, p=0.027) or to say they would be upset if their child or loved one smoked cannabis (χ2=4.39, p=0.044). Education: Participants with a higher level of education were more likely to believe cannabis could cause harm medically (χ2=10.24, p=0.006), and were less likely to see cannabis use as a moral issue (χ2=6.99, p=0.030). There was also a trend toward participants with higher education being less likely to use cannabis currently (χ2=5.65, p=0.059). Employment: Participants who reported being employed were more likely to say they used cannabis for recreation (χ2=5.35, p=0.033), and less likely to say they used cannabis for pain (χ2=8.81, p=0.007) or spasticity (χ2=13.25, p=0.000). Disease course: The breakdown of participants currently using cannabis according to disease course was: 33 with RRMS (75%); 4 with PPMS (9.1%) and 7 with SPMS (15.9%). These differences were not significant. (χ2=1.93, p=0.381). Disability: Subjects with higher disability (indicated by scores between 4 and 8 on the PDDS) were more likely to approve of cannabis use (χ2=12.58, p=0.002), but this did not translate into more frequent current use (χ2=0.126, p=0.723). Clinic site: Comparisons were undertaken between participants attending the neurology and neuropsychiatric clinics. The two groups did not differ in their frequency of current use (χ2=1.6, p=0.66), but lifetime use differed significantly with 71 (66.7%) of the psychiatric group versus 54 (46.15%) in the neurology group acknowledging use (χ2=9.79, p=0.002). Neuropsychiatric clinic attendees were also more in favour of legalization (χ2=6.18, p=0.045), more likely to accept cannabis from a friend or family member (χ2=4.61, p=0.034), and to report using cannabis for managing depression (χ2=5.00, p=0.039), but not anxiety (χ2=2.743, p=0.09). In addition, subjects who reported using anti-anxiety medication were significantly more likely to report currently using cannabis (χ2=9.34, p=0.004).
Demographic and neurologic data.
|Age||47.56 (SD=11.82) years|
|High school||52 (23%)|
|Relapsing remitting||136 (61%)|
|Primary progressive||22 (10%)|
|Secondary progressive||64 (29%)|
There were no demographic or disease related differences between current cannabis (N=44) users attending the neuropsychiatry and neurology clinics (see Table 2a). However, those attending the neuropsychiatry clinic reported a higher frequency of use for multiple symptoms, with these differences achieving statistical significance for pain and depression (see Table 2b).
- A. Attitudes toward Cannabis: With respect to the entire sample's (n=225) attitudes toward cannabis, 122 (54.3%) approved of it while 75 (33.2%) were neutral. Legalization in general was endorsed by 98 (43.7%) with an additional 98 (43.7%) in favour of legalization for medical use only. If the drug were legalized, 113 (50.2%) said they would use it. More individuals viewed the drug as helpful 197 (87.6%) than harmful 108 (47.9%), although the majority, 177 (78.7%), believed cannabis could cause problems with memory or attention. Eighty seven subjects (38.6%) viewed cannabis use as a moral issue. Only 14.1% (n=32) of subjects said their feelings toward a friend would change if they discovered that the friend used cannabis, although 48.8% (n=110) said they would be upset if their child or loved one used it. Sixty four (28.6%) subjects divulged they would feel uncomfortable if people around them were using cannabis while 78 (34.7%) said they would accept a “puff” if offered by friend or family member.
Demographic information of MS subjects currently using cannabis (n=44) attending a neuropsychiatric and a neurological clinic.
|Measure||Overall mean (sd) N=44||Neuropsychiatry Mean (sd) N=25||Neurology mean (sd) N=19||t-score/χ2||p value|
|Mean Age, years (STD)||46.4 (11.2)||47.4(10.1)||45.0 (12.5)||t=0.70||p=0.56|
|Gender (female)||22||15||7 Female||χ2=2.32||p=0.13|
|PDDS||2.69 (2.4)||3.13 (1.6)||2.42 (2.4)||t=1.1||p=0.26|
|Duration of MS (years)||3.1(0.85)||3.28(0.74)||2.8 (0.92)||t=0.15||p=0.88|
PDDS=Patient Determined Disability Steps.
Frequency of cannabis use according to symptom: comparisons between people with MS attending a neuropsychiatry and a neurology clinic.
|Symptoms||Overall N=44||Neuropsychiatry N=25||Neurology N=19||χ2||p value|
|Sleep||36 (82%)||21 (48%)||15 (34%)||χ2= 0.5||p=0.82|
|Pain||33 (75%)||22 (50%)||11 (25%)||χ2=3.85||p=0.05|
|Anxiety||32 (73%)||21 (48%)||11(25%)||χ2=2.74||p=0.09|
|Spasticity||30 (68%)||20 (45%)||10(23%)||χ2=2.88||p=0.09|
|Depression||23 (52%)||17 (39%)||6 (14%)||χ2=4.99||p=0.03|
|Recreation||24 (55%)||12 (27%)||12 (27%)||χ2=0.87||p=0.35|
|Bladder Control||8 (18%)||6 (14%)||2 (5%)||χ2=1.35||p=0.25|
Our study revealed that one in five people with MS use cannabis, the majority on a daily basis. Just over half have tried cannabis at some point in their lives with close to 90% approving of the drug albeit for different reasons. The data come from a consecutive sample of clinic attendees with an age, gender and disease course composition suggesting the sample overall is representative of the broader MS population (Koch-Henriksen and Sørensen, 2010).
The percentage of subjects currently using cannabis is similar to that reported a decade back. (Clark et al, 2004) and (Wade et al, 2006) Indeed this MS figure has shown a remarkable consistency across time and place (Chong et al, 2006 and Page et al, 2003). While direct comparisons across studies need to be read with caution given the possibility of demographic and disease related mismatch, the percentage of people with MS in our study who divulged ever having used cannabis was one third higher than that reported in another Canadian study a decade earlier notwithstanding the fact that the percentage of current users overlapped. Why this should be is unclear. However it is plausible to speculate that lifetime prevalence rates in people with MS follow the general population trend which has shown an increase with time (Topline at al., 2015). The same is likely true for attitudes towards the drug, which in our study was strongly positive notwithstanding some concerns about potential side effects, most notably cognitive difficulties. This last point is of interest given that awareness of impaired cognition has increased amongst the MS community, including treating neurologists, over the past few decades. Here a recent study of symptom concern amongst people with MS placed cognitive dysfunction high on their list (Heesen et al., 2008).
Attitude toward cannabis amongst people with MS do, however, vary according to sample selection and are influenced by demographic characteristics. Our data reveal that lifetime use is significantly more frequent amongst those attending a neuropsychiatry rather than a neurology clinic within the same hospital, a result that can be possibly linked to co-morbidity, namely an association with anxiety and depression. The non-MS general psychiatry population supports this finding too with a robust correlation found between these disorders and cannabis use (Degenhardt et al, 2001, Degenhardt et al, 2003, and Moore et al, 2007). Reasons for using cannabis appear to be consistent over time with pain and spasticity always featuring prominently across MS studies (Consroe et al, 1997, Ware et al, 2010, and Corey-Bloom et al, 2012), but once more these can vary according to sample bias. Not surprisingly, our study revealed that anxiety and depression were more frequently given as a reason for use in a neuropsychiatry population.
There is a significant difference between the genders not only in their frequency of use, but also in their attitudes towards the drug. Once more, the MS findings mirror those reported in the general population (Anderson, 2001 and Center for Behavioral Health Statistics and Quality, 2015). Another notable finding was that subjects with a higher education were more concerned about cognitive side effects, perhaps reflecting this group's better knowledge of the MS-cannabis literature, where emerging data have revealed more extensive memory, processing speed and executive deficits associated with inhaled cannabis (Pavisian et al, 2014 and Honarmand et al, 2011).
Our study is not without limitations. We relied on self-report responses rather than structured interviews to obtain the data. This leaves the symptom data open to bias, particularly in the context of subjects with depression and anxiety. This was evident in the comparisons between subjects attending the two different clinics. Although there were no demographic or disease related differences between these two groups, the neuropsychiatric sample endorsed significantly more symptoms for which they were taking cannabis.
In summary, our data show a broad degree of acceptance towards cannabis use by people with MS. Approximately one in five individuals currently use the drug, most often on a daily basis and for a multiplicity of symptoms. Notwithstanding the ease with which the cannabis can now be legally obtained in Ontario for medical reasons, concerns persist amongst people with MS about the legality of use. Our data suggests the number of cannabis users could therefore increase significantly if the legal barrier was removed. With Canada having the highest incidence of MS in the world (MSIF, 2013) and with around 100,000 Canadians affected by the disease, what to make of cannabis as a medicinal agent is a question that deserves attention. As our data show, significant numbers of people with MS are already using the drug in the absence of empirical data for and against it. The challenge faced by the medical profession in the years ahead is to play catch-up and help our patients make an informed choice.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Emma Banwell reports no disclosures.
Bennis Pavisian reports no disclosures.
Liesly Lee reports no disclosures.
Dr. Anthony Feinstein has served on scientific advisory boards for Merck Serono and Avanir Pharmaceuticals; has received speaker honoraria from Merck Serono, Teva Pharmaceutical Industries Ltd., Bayer Schering Pharma, and Biogen Idec; serves on the editorial boards of Multiple Sclerosis; receives publishing royalties for The Clinical Neuropsychiatry of Multiple Sclerosis (Cambridge University Press, 2007); chairs the Medical Advisory Committee for the Multiple Sclerosis Society of Canada; conducts neuropsychiatric evaluation, cognitive testing, brain imaging in neuropsychiatry in his clinical practice; and receives research support from the Canadian Institute of Health Research, the Multiple Sclerosis Society of Canada and Biogen Idec.
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