The COVID-19 pandemic and cannabis use in Canada―a scoping review

Article type: Review Article

Keywords: COVID-19, Cannabis, Scoping review, Canada

Authors: Kelda Newport, Lisa Bishop, Jennifer Donnan, Shefali Pal, Maisam Najafizada ⚬

Affiliations: grid.25055.370000 0000 9130 6822School of Pharmacy, Memorial University of Newfoundland and Labrador, St. John’s, NL A1B 3V6 Canada; grid.25055.370000 0000 9130 6822Faculty of Medicine, Memorial University of Newfoundland and Labrador, 300 Prince Phillip Drive, NL A1B 3V6 St. John’s, Canada

License: © The Author(s) 2023 CC BY 4.0 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Article links: DOI: 10.1186/s42238-023-00196-7  |  PubMed: 37525289  |  PMC: PMC10388476

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Introduction

Since the legalization of nonmedical use of cannabis in Canada in 2018, the cannabis industry has evolved rapidly (Rotermann ref. 2020). The COVID-19 pandemic and the federal and provincial public health emergency orders implemented in response to the pandemic affected the cannabis consumption patterns in a multitude of ways. During the pandemic, provinces and territories have ordered full lockdowns and other restrictive measures on businesses to help curtail the spread of the virus (Canadian ref. 2021). Businesses have also had to adapt to the changing environment. Physical retail outlets took steps to reduce in-person interactions and close contact primarily by implementing physical distancing measures within stores, increasing sanitation measures, reducing operating hours, and where possible providing curbside pickup or online sales (Canadian ref. 2022).

The COVID-19 pandemic and associated public health measures implemented to reduce transmission of the SARS-CoV‐2 virus has had direct and indirect consequences on cannabis consumption, many of which are preliminary and continue to be researched (Statistics ref. 2021; Canadian ref. 2020; Canadian ref. 2021). In Canada, the sale of cannabis falls under provincial and territorial jurisdiction and during the initial pandemic lockdowns, most jurisdictions either declared or treated the non-medical retail sale of cannabis as an essential service (Canadian ref. 2021). Retail sales of cannabis, for example, increased across Canada except for Prince Edward Island after the initial waves of the pandemic (Myran ref. 2020). One poll conducted earlier in the pandemic showed that cannabis consumption in Canada remained stable (Canadian ref. 2020), while a second poll indicated that the frequency and quantity of cannabis use increased by over 30% among those who consumed cannabis (Canadian ref. 2020). A Canadian Centre on Substance Use and Addiction (CCSA) study in 2022 reported that purchases from licensed retailers had been increasing as the two most common avenues of purchase in 2020 were from legal physical and online stores (Canadian ref. 2022). Moreover, the consumption method has been shifting slightly from smoking to edible products as they become more available through legal channels (Canadian ref. 2022).

The impact of the pandemic on cannabis consumption in Canada and, specifically, whether health- and socioeconomic-related changes and stresses have impacted patterns of use, is of particular interest as we enter the fifth year of cannabis legalization in Canada―a time and opportunity for policy adjustment. The objective of this scoping review was to describe the patterns of consumption and cannabis-related health and safety considerations during the COVID-19 pandemic in Canada. A scoping review was conducted to systematically map the research in this area, identify gaps in existing knowledge, and make recommendations for future research.

Methods

Due to the evolving nature of the pandemic with rapidly emerging evidence, a scoping review was deemed to be the most appropriate method (Levac et al. ref. 2010). We adopted the five-stage scoping review methodology developed by Arksey and O’Malley: (1) identify the research question; (2) identify the relevant studies; (3) indicate the inclusion and exclusion criteria; (4) chart the data; and (5) collate, summarize, and report the results. Arksey and O’Malley define a scoping review as “a technique to ‘map’ relevant literature in the field of interest … [which] tends to address broader topics where many different study designs might be applicable …” (Arksey and O’Malley ref. 2005). The Joanna Briggs Institute (JBI) guidelines on scoping reviews were also adopted to guide our methodology and align with current reporting standards in evidence synthesis (Peters et al. ref. 2015). Reporting was also informed by the PRISMA Extension for Scoping Reviews (Tricco et al. ref. 2018).

This review was initiated with the question “What impact has the COVID-19 pandemic had on cannabis consumption and health and safety issues related to cannabis in Canada?” The search strategies were developed in consultation with a librarian and through team discussion. Electronic databases (PubMed, CINAHL Plus, Embase, and Web of Science) were searched according to the search strategy presented in Table 1 and supplemented with searching Google Scholar, Public Health Agency of Canada website, and Google search engine for grey literature.

Article titles and abstracts resulting from the database and grey literature searches were screened independently by two authors (KN, SP). Full texts were then screened by both authors for potentially relevant publications. Disagreements on study selection and data extraction were resolved by consensus and discussion with a third author (MN) when necessary. The original search was conducted in May 2021 and updated on September 24, 2021.

Peer-reviewed or pre-print studies of Canadian data using any study design and grey literature reporting Canadian real-world data were included if they were published in English between March 1, 2020, and September 24, 2021, and focused on cannabis and COVID-19 in Canada. We broadly searched for literature related to cannabis, and although we did not intentionally search for medical cannabis, we included papers that reported on medical and non-medical cannabis. Media reports, editorials, opinion pieces, blog posts, and pharmacological papers were excluded. Papers in which specific cannabis data could not be separated from the aggregate data were also excluded. Inclusion and exclusion criteria are listed in Table 2.

A comprehensive data charting form was developed to extract relevant information from included sources of evidence. Abstracted data on study characteristics included: study author(s), date of publication, publication journal, location(s) of study, study population, sample size, study type, objectives, and key findings. One author (KN) charted the data and all authors discussed the results and continuously updated the data-charting form in an iterative process.

A content analysis is a research method that can be used to identify patterns across qualitative data, which often provides frequency counts and allows for quantitative analyses of qualitative data (Braun and Clarke ref. 2006). We conducted a thematic content analysis to identify, analyze, and report patterns and themes and to establish how the identified themes fit together to tell a narrative about the data (Braun and Clarke ref. 2014). A paragraph was the unit of analysis in the coding process. A single paragraph was coded multiple times when needed. The codes were then merged into sub-themes and themes. An initial list of themes was provided to the authors but the authors could identify new themes from the data as well―a mix of a deductive and inductive approach.

Results

A total of 132 references were initially identified, of which 69 full-text records were assessed for eligibility, and 21 records met the inclusion/exclusion criteria and were included in the scoping review (Fig. 1).

Seventeen of the included studies present results from cross-sectional surveys (Myran ref. 2020; Canadian ref. 2020; Currie ref. 2021; Dozois ref. 2021; Dumas et al. ref. 2020; Farhoudian et al. ref. 2020; Imtiaz et al. ref. 2021; Joyce et al. ref. 2020; Prowse et al. ref. 2021; Rotterman ref. 2020; Rotterman ref. 2021; Statistics ref. 2021; Turna ref. 2021; Turna et al. ref. 2021; Turner ref. 2019; Vedelago et al. ref. 2022; Zajacova et al. ref. 2020). The remaining four include an ecological study (Canadian ref. 2021), a conceptual model (Enns et al. ref. 2020), a prospective cohort study (Leatherdale et al. ref. 2021), and a longitudinal study (Bartel et al. ref. 2020). Eighteen studies were conducted solely in Canada (Canadian ref. 2021; Myran ref. 2020; Canadian ref. 2020; Currie ref. 2021; Dozois ref. 2021; Dumas et al. ref. 2020; Imtiaz et al. ref. 2021; Joyce et al. ref. 2020; Prowse et al. ref. 2021; Rotterman ref. 2020; Rotterman ref. 2021; Statistics ref. 2021; Turner ref. 2019; Vedelago et al. ref. 2022; Zajacova et al. ref. 2020; Enns et al. ref. 2020; Leatherdale et al. ref. 2021; Bartel et al. ref. 2020), and the remaining three studies included global data, including Canadian data (Farhoudian et al. ref. 2020), data from Canada and the United States (US) (Turna et al. ref. 2021), or data collected from Canada, US, Brazil, and Italy (Turna ref. 2021). A summary of the scoping review study data can be found in Table3 and characteristics of included studies can be found in Table 4.

Content analysis

There was a mixture of information about the studies and factors relating to cannabis consumption during the pandemic. The population sample in the studies included in this review were general population adults [11], mothers [1], adolescents and youth (e.g., grade students, undergrad students) [5], healthcare practitioners [2], emergency department patients [1], and cannabis users [1]. One study found that cannabis use in the overall population remained stable during the early months of May and June 2020; however, they noted that during the same period, cannabis consumption among those who were prior cannabis consumers increased by half compared to before the pandemic (Imtiaz et al. ref. 2021). Data from January 2021 from the Canadian Perspectives Survey Series (CPSS) 6: Impacts of COVID-19, which is a representative sample of the Canadian Population aged 15 years and older, also indicated that of those who had previously consumed cannabis, more than one third (34%) reported their consumption had increased during the pandemic (Statistics ref. 2021).

Content analysis suggested that cannabis consumption during the pandemic varied by reasons for use, consumers’ age, gender, and method of consumption. The accentuated health impacts of cannabis consumption during the pandemic was also recorded. Our findings are described in more detail in the following sections and Tables 5, 6, 7, 8, 9 and 10.

Reasons for cannabis consumption

Nine of the included studies reported either an increase or a decrease in the consumption of cannabis during the pandemic due to a variety of reasons, as summarized in Table 5. Some of the key findings with regard to reasons for increased and decreased cannabis consumption can be found in Table 6.

Multiple studies indicated that self-isolation, loneliness, and boredom (Statistics ref. 2021; Enns et al. ref. 2020), anxiety, stress, and depression (Canadian ref. 2020; Statistics ref. 2021; Bartel et al. ref. 2020), and ease of access (Joyce et al. ref. 2020; Enns et al. ref. 2020)were all reasons for increased consumption. A 2021 survey of Canadians reported that stress (65%), boredom (58%), and loneliness (39%) during the pandemic were factors that contributed to increased consumption (Enns et al. ref. 2020). Similar factors reported by the Canadian Center for Substance Abuse and Addiction (CCSA) included lack of schedule (57%), stress (56%), boredom (55%), and loneliness (16%) (Statistics ref. 2021). Adults who were self-isolating had increased consumption by 20%, in contrast to those not self-isolating (Canadian ref. 2020). Dozois (ref. 2021) found that with social distancing restrictions, 29% of individuals reported an increase in cannabis use (Dozois ref. 2021). Similar to what was reported by adults, adolescents reported boredom and availability of free time as reasons for the increased use of cannabis during the pandemic (Imtiaz et al. ref. 2021).

Canadians with self-assessed fair to poor mental health were two times more likely to have increased their cannabis consumption (Dozois ref. 2021). Consumption also increased by 31% during the pandemic among those who always consumed cannabis to cope with depression (Canadian ref. 2020). Mothers reported increased substance use to cope with anxiety, depression, or with younger children during the pandemic (Bartel et al. ref. 2020).

The CPSS reported other factors related to access that contributed to increased consumption, which included convenience (38%) (e.g., lack of a regular schedule, at home often) and ease of access (29%) (e.g., availability of online shops, increase in retail stores, delivery, curbside pickup) (Statistics ref. 2021).

Among respondents who reported decreased consumption over the pandemic in the Canadian national survey, the reasons included the negative effects of cannabis (64%), decreased opportunities for socializing (28%), and personal (e.g., family and work obligations) responsibilities (16%) (Statistics ref. 2021). Two other factors associated with decreased consumption included higher education (Prowse et al. ref. 2021)and using with parents (Bartel et al. ref. 2020).

Age variation

Our review found 6 studies reporting on age variation of cannabis consumers during the pandemic. Key findings are reported here and in Table 7.

Compared to older adults, younger people were more likely to have increased their consumption since the start of the pandemic (Statistics ref. 2021). Among respondents aged 15 to 29 who had previously consumed cannabis, 43% reported increasing their consumption during the pandemic (Statistics ref. 2021). By comparison, 20% of respondents aged 50 to 64 and 22% of those aged 65 or older reported a consumption increase (Statistics ref. 2021). Similarly, data from a cross-sectional study in Canada found significant increases in cannabis use among participants < 35 years compared to those ≥ 60 (Turner ref. 2019). Findings from Turner et al. (ref. 2021) suggest that young people may be particularly impacted by behavior changes due to the early months of the pandemic.

Cross-sectional data collected between May to July 2020 from youth in grades 9 to 12 in Ontario and Secondary I–V in Quebec identified that the majority who consumed cannabis did not report increased cannabis use due to COVID-19 or using cannabis to cope with COVID-19 (Leatherdale et al. ref. 2021). However, Leatherdale et al. (ref. 2021) found that although youth cannabis consumption in Canada increased between 2019 and 2020, the increase was not as high as expected had the pandemic not happened, supporting the claim that the pandemic had either slightly reduced the prevalence of consumption among youth in Canada or did not have a significant impact (Leatherdale et al. ref. 2021).

Gender differences

Three studies reported key findings on differences in cannabis consumption between genders. These findings are reported here and in Table 8.

Dumas et al. found that, in April 2020, the percentage of cannabis-using adolescents aged 16–18 decreased for girls only (3% decrease, from 16 to 13%), and yet, the frequency of cannabis use (average number of cannabis using days) increased significantly for girls (Dumas et al. ref. 2020), an increase which was not seen for boys.

The context of cannabis consumption also differed between genders. Dumas et al. found that increased cannabis use in the context of solidarity and face-to-face with peers was observed more in boys (58% and 31%, respectively) than girls (46% and 22%, respectively). Moreover, mixing cannabis with other substances was also more prevalent among boys (Dumas et al. ref. 2020). On the other hand, more girls used substances with their parents (47%) and engaged with acquaintances through social posts (40%) in contrast to boys (30% and 24%, respectively).

The transition of in-person learning to online learning has significantly impacted the mental health of female students (25.4%) than male students (15.5%); however, male students reported a higher rates of cannabis use to cope with pandemic stress and schoolwork than their female counterparts (Prowse et al. ref. 2021). Male students also reported using cannabis, alcohol, and vaping nicotine to cope with the negative impact of the pandemic including stress, mental health (Prowse et al. ref. 2021), and increased hospitalization rate (Rotterman ref. 2021).

Method of consumption

Our review found 2 studies that reported findings on methods of cannabis consumption during the pandemic which are explained here and in Table 9. While data is lacking on all methods of consumption during the pandemic, smoking was reported as the most commonly used method of consumption of cannabis for both males and females (Rotterman ref. 2021; Bartel et al. ref. 2020). Data collected by The National Cannabis Survey (NCS), which collected data from mid-November to December 31, 2020, reported that about 7 in 10 Canadians who reported using cannabis consumed dried flower or leaf (Rotterman ref. 2021).

Health and safety impacts related to cannabis use during COVID-19

The indirect effects of the pandemic including the impacts of public health measures taken to control the spread of COVID-19 and the psychosocial impacts of the pandemic environment such as worry and fear have led to unintended health consequences during the pandemic (Canadian ref. 2021). Two of the included studies reported findings on the health and safety impacts are detailed here and in Table10. The Canadian Institute of Health Information (CIHI) reported that more Canadians received substance-related hospital care during the COVID-19 pandemic than in the previous year. A substantial increase was observed in both emergency departments (ED) visits and hospitalizations for cannabis-related harms for the period of March to September 2020 compared with the same period in 2019. Specifically, there was an 8% increase in ED visits and a 5% increase in cannabis-related hospitalizations (Canadian ref. 2021). Currie (ref. 2021) found adults who believed they would contract COVID-19 in the next year had increased their substance use (alcohol and/or cannabis) and thus reported more pandemic-related PTSD symptoms, than those who did not believe they would contract COVID-19 (Currie ref. 2021). Data collected in June 2020 from 933 community-based adults in Alberta found high pandemic-related PTSD symptoms were associated with more than a twofold increase in the odds of increased substance use (alcohol and/or cannabis) in the past month among both women and men (Currie ref. 2021).

Discussion

In this scoping review, we identified 21 records that addressed the impact of the pandemic on patterns of use and cannabis-related health and safety in Canada. Our findings suggest that the impact of the pandemic on cannabis consumption in Canada is more complex than simplistic assumptions of increase or decrease. The association appears to be based on the characteristics of the consumers such as age, gender, type of user (occasional/frequent), reasons for use, and accentuated health impacts.

Our findings match those of other countries and portray a mixed picture with respect to cannabis use during the pandemic (Farhoudian et al. ref. 2020; Turna ref. 2021; Manthey et al. ref. 2021; Vanderbruggen et al. ref. 2020; van Laar et al. ref. 2020; European ref. 2021). An online survey of 21 European countries found that the pattern of change in cannabis consumption across Europe during the pandemic was not clear; however, on average, consumers reported an increase in use (Manthey et al. ref. 2021). Similarly, a global survey found that approximately 42% of participating countries reported that cannabis consumption increased, whereas 26% and 22% reported a decrease and no change in cannabis use pattern, respectively (Farhoudian et al. ref. 2020). Interestingly, a survey in Belgium found there were no significant changes in cannabis consumption noted in the period before and during the COVID-19 lockdown suggesting social isolation did not influence cannabis consumption (Vanderbruggen et al. ref. 2020).

Similar to findings in Canada, cannabis consumption patterns in the Netherlands may have changed more among regular consumers during the pandemic (van Laar et al. ref. 2020). In addition, data available from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) suggests that some occasional users may have stopped using or reduced their cannabis use during the lockdown period, while those who had more frequent or intensive patterns of use may have increased their consumption (European ref. 2021). These findings are similar to patterns seen in Canada (Imtiaz et al. ref. 2021).

Motives that drove the increased consumption of cannabis during the pandemic appear to be similar around the globe. Top reasons reported for consuming cannabis more during the pandemic included boredom and loneliness (Vanderbruggen et al. ref. 2020; van Laar et al. ref. 2020). However, an interesting difference was noted when comparing healthcare practitioners in Italy, Brazil, and the USA to those in Canada where Canadian practitioners reported increasing their cannabis consumption during the pandemic to cope with stress and anxiety (Turna ref. 2021).

Gender-specific considerations influencing cannabis consumption are important to consider for prevention and public education as the pandemic evolves. While the CCSA’s 2021 report “Differences in Cannabis Perceptions among Canadian Adolescent Boys and Girls’’ reported that boys and young men reportedly use cannabis more frequently and heavily than girls and young women (Goodman ref. 2021), our scoping review found that in the context of COVID-19, cannabis use among female youth increased during the COVID-19 pandemic compared to male youth. Furthermore, there was a greater reduction in the expected escalation of cannabis use among males compared to females, suggesting cannabis consumption among males may be more socially driven than among females (Dumas et al. ref. 2020; Leatherdale et al. ref. 2021). As the effects of the pandemic extend beyond the disease itself, it has become imperative to understand the short and long-term consequences of the pandemic and understand the impacts for specific segments of the population, including variation between genders. Informing mitigation strategies with ​​a gender-specific understanding of patterns of use is important.

Smoking cannabis continued to be the most common method of consumption at the end of 2020. Evidence supports the concern that cannabis smoke can negatively affect heart and lung health (Canadian ref. 2020). The extent to which cannabis smoke impacts respiratory and immune health in humans is not well-known and further studies are needed to confirm these relationships (Canadian ref. 2020). This is concerning in the context of the pandemic as smoking cannabis has been linked to increased risk for COVID-19 complications and related death (Canadian ref. 2020). In light of the ongoing pandemic, behaviors that might put an individual’s health at risk should be carefully considered. Furthermore, given smoking continues to be the most common method of consumption, it highlights a need for evidence-informed cannabis education, and in particular, with regards to Canada’s lower-risk cannabis use guidelines (Fischer et al. ref. 2017).

Despite the effect of above factors on cannabis consumption during the pandemic, there are methodological issues that needs to be considered for interpretation and that are not explored in this study. The heterogeneity of findings could be due to difference in study designs and qualities. Due to the short timeframe between the pandemic and this study, follow-up length and baseline cannabis use could impact the consumption patterns that are captures in studies reviewed in this manuscript.

This scoping review identified several implications for future research and practice. Frequent cannabis consumers who are adolescents, young adults, mothers, and frontline workers require more attention for further research. The COVID-19 pandemic and measures to control it have caused a range of mental health issues leading to increased consumption to address those issues; however, this review did not find evidence of the benefits from consuming cannabis. Understanding the cycle of mental health and substance use is important to inform decisions and policies to facilitate greater availability of, and accessibility to, mental health and substance use services as the COVID-19 pandemic evolves and for future public health crises. In particular, further research is needed to understand the changes in cannabis consumption during the pandemic and how these changes have impacted health and safety that will be relevant post-pandemic. It would also be interesting to investigate the role of therapeutic cannabis use among regular cannabis users, during an unprecedented pandemic.

This scoping review includes a number of limitations. Many of the included studies were conducted relatively close to the beginning of the pandemic, therefore, routines may have not been established and the possible full impact of the pandemic not captured. Many of the studies reviewed used self-reported cannabis use and self-perceived changes during the pandemic. Subjectivity can be both a strength and a limitation, depending on different epistemological perspectives. In addition, the review is dependent on information on the review question being available and since the pandemic is ongoing there may be gaps in evidence. It is also possible that relevant sources of information may have been omitted. Finally, as is the case for all scoping reviews, no rating of quality or level of evidence is provided; therefore, practice recommendations cannot be graded.

Conclusion

As we learn to live with COVID-19, its impact on and its relations with cannabis in Canada is an issue of importance. This scoping review synthesized rapidly growing knowledge on the relationship between the pandemic and cannabis consumption in Canada. This review suggested that the impact of the pandemic on cannabis consumption in Canada is more complex than simplistic assumptions of increase or decrease and it continues to be difficult to measure. The association depends on the characteristics of the consumers such as age, gender, reasons for increased and decreased use, and method of consumption. As the COVID-19 continues to evolve, high-quality evidence is needed to inform how public health-related policies and practices on cannabis can protect vulnerable groups such as young adults and frequent consumers, and future research should focus on better understanding considerations for mental health among cannabis consumers.

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