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Article

Co-Use of Alcohol and Cannabis During COVID-19: Associations Between Sociodemographic Factors and Self-Reported Mental Health Symptoms and Heavy Episodic Drinking in Canadian Adults

by
Nibene H. Somé
1,2,3,4,*,
Sameer Imtiaz
5,
Yeshambel T. Nigatu
5,
Samantha Wells
3,5,6,7,8,
Claire de Oliveira
2,4,5,6,
Shehzad Ali
3,9,10,11,12,
Tara Elton-Marshall
13,
Jürgen Rehm
5,6,7,14,15,
Kevin D. Shield
3,5 and
Hayley A. Hamilton
5,6
1
Ontario Health, Toronto, ON M5G 2L3, Canada
2
Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5T 3M6, Canada
3
Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON N6G 2M1, Canada
4
Institute for Clinical Evaluative Sciences, Toronto, ON M4N 3M5, Canada
5
Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, ON M5S 2S1, Canada
6
Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada
7
Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada
8
School of Psychology, Deakin University, Victoria, VIC 3220, Australia
9
Schulich Interfaculty Program in Public Health, Schulich School of Medicine and Dentistry, Western University, London, ON N6G 2M1, Canada
10
Department of Health Sciences, University of York, York YO10 5DD, UK
11
Department of Psychology, Macquarie University, Sydney, NSW 2109, Australia
12
Bruyere Research Institute, Ottawa, ON K1N 5C8, Canada
13
School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, ON K1G 5Z3, Canada
14
Institute for Clinical Psychology and Psychotherapy, TU Dresden, 01187 Dresden, Germany
15
Institute of Medical Science, University of Toronto, Toronto, ON M5S 3H2, Canada
*
Author to whom correspondence should be addressed.
Psychoactives 2025, 4(3), 27; https://doi.org/10.3390/psychoactives4030027
Submission received: 9 May 2025 / Revised: 29 July 2025 / Accepted: 31 July 2025 / Published: 6 August 2025

Abstract

This study estimates the prevalence of co-use of alcohol and cannabis, assesses the sociodemographic risk factors of co-use, and examines the associations between mental health and heavy episodic drinking (HED) and alcohol–cannabis co-use in Canada during the early years of the COVID-19 pandemic. Nine successive cross-sectional surveys, held from May 2020 to January 2022, of adults (aged ≥18 years) living in Canada were pooled for 9011 participants. The prevalence of co-use was calculated across sociodemographic groups. Logistic regressions were used to assess associations. Alcohol–cannabis co-use was associated with a greater likelihood of engaging in HED and experiencing symptoms of anxiety, depression, and loneliness. The prevalence of co-use of alcohol was different across sociodemographic groups. The highest prevalence was among TGD people (35.5%), followed by individuals aged 18–39 years (14.5%). Additionally, being TGD (aOR = 3.61, 95% CI 2.09–6.25), separated/divorced/widowed (aOR = 1.60, 95% CI 1.23–2.07), living in an urban area (aOR = 1.26, 95% CI 1.07–1.56), and having a high household income (aOR = 1.41, 95% CI 1.09–1.82) increased the likelihood of reporting alcohol–cannabis co-use. These findings underscore the fact that developing public health and clinical interventions for preventing and treating excessive alcohol or cannabis use must consider both alcohol and cannabis use patterns and should be tailored to the highest-risk TGD and young adults.

1. Introduction

Alcohol and cannabis are the two most commonly used psychoactive substances in Canada [1,2]. The use of these substances by Canadians leads to a substantial burden of health and social harms. In particular cannabis 287 deaths in Canada in 2012 [3], and alcohol use caused 17,098 deaths in Canada in 2020 [4]. The COVID-19 pandemic and the associated social distancing policies further increased problematic alcohol and cannabis consumption in Canada [1,2,5]. In 2021, 18% of Canadians 15 years of age and or older reported consuming five or more drinks on days they had consumed alcohol in the previous month; this proportion was higher than what was recorded before the pandemic (11% in 2017) [1]. Also, among Canadians who had previously consumed cannabis, 34% reported increased consumption during the pandemic, compared with the pre-pandemic period [1]. Evidence suggests there is a strong association between cannabis and alcohol use [6,7,8,9]. Among alcohol users, cannabis is the most widely used substance (excluding alcohol) [10,11]; similarly, most cannabis users report using alcohol [12]. Simultaneous use of alcohol and cannabis is considered a risk for users’ safety and well-being [7,13], mainly because of its additive effects [14,15,16]. The alcohol–cannabis co-use (i.e., the use of both substances within a given period of time [10,16]) is associated with increased risk of serious public health concerns, including unsafe driving behaviours, including heavy episodic drinking (adults in the United States were 3.7 times more likely to binge drink in the past month if they used cannabis in the past month) [16,17], and higher rates of alcohol use disorders [16,18,19].
Alcohol–cannabis co-use is also associated with an increased prevalence of mental illness [16,18]. Indeed, co-use increases the risk of behavioural problems, psychosis, and substance-related harms [20,21]. Although the use of cannabis is associated with the development of mood disorders and anxiety disorders as well as loneliness [16,18,22], and the use of alcohol is causally related to the development of mood disorders and associated with loneliness [22,23], it is currently unknown if anxiety, mood disorders or loneliness are associated with co-use of cannabis and alcohol.
Given that alcohol–cannabis co-use affects the health outcomes for the general population, it is imperative to understand co-users better and provide new insights that may inform interventions and prevention strategies to reduce its burden. However, despite these concerns about the additive harms of alcohol and cannabis co-use, limited research has explicitly examined the prevalence of and the sociodemographic risk factors associated with alcohol and cannabis co-use compared to the exclusive use of either substance among Canadians [24,25]. Most studies investigating risk factors of co-use have focused on adolescents and young adults (aged 12–25), and most of this work has only examined the role of age, gender, and ethno-racial background [24]. Furthermore, results of previous studies have been mixed in terms of which sociodemographic factors affect co-use, particularly regarding gender and ethno-racial background [25,26,27,28]. A study examining co-use among adults in the US found that this behaviour was strongly associated with being younger (aged 18–49) and having less than a high school education [29]. The examination of the association between non-binary gender and polysubstance use has focused mainly on transgender and gender-diverse individuals (i.e., those whose gender identity differs from their assigned sex at birth [30]) [31]. A cross-sectional study on 32,072 students in the US, including 335 transgender and gender-diverse individuals, examined the simultaneous use of alcohol, cigarettes, cannabis or other drugs within the previous 30 days [32]. Transgender adolescents were five times more likely to use multiple substances compared to their cisgender peers (i.e., those whose gender identity aligned with their assigned sex at birth [30]) [31].
The present study extends the investigation of alcohol–cannabis co-use using repeated cross-sectional surveys conducted in Canada during the COVID-19 pandemic to understand the harms and risk factors associated with this behaviour. The specific objectives of this study are to (1) estimate the prevalence of alcohol–cannabis co-use across sociodemographic groups, including age, gender (i.e., women, men, and transgender and gender diverse people), ethno-racial background and socioeconomic status (i.e., employment status, household income, and educational attainment); (2) identify specific sociodemographic risk factors associated with alcohol–cannabis co-use, and (3) examines the associations between mental health and heavy episodic drinking and alcohol–cannabis co-use in Canada during the early years of the COVID-19 pandemic.

2. Material and Methods

2.1. Participants and Data Collection

Data were obtained from nine repeated web-based cross-sectional surveys conducted with English-speaking Canadian adults aged 18 years and older. The firm Delvinia collected the survey data through Asking Canadians (http://www.delvinia.com/solutions/askingcanadians (accessed on 5 May 2025)), utilizing proportional quota sampling to mirror the distribution of the English-speaking Canadian population by age, sex, and region [33]. Participants completed electronic consent forms prior to starting the survey, and the study received ethics approval from the Centre for Addiction and Mental Health. The surveys were conducted from May 2020 to January 2022, with the following timeline: Survey 1: 8–12 May (n = 1005, response rate (RR) = 15.9%), Survey 2: 29 May–1 June (n = 1002, RR = 17.2%), Survey 3: 19–23 June (n = 1005, RR = 16.4%), Survey 4: 10–14 July (n = 1003, RR = 13.7%), Survey 5: 18–22 September (n = 1003, RR = 17.6%), Survey 6: 27 November–1 December (n = 1003, RR = 16.2%), Survey 7: 19–23 March (n = 1000, RR = 15.8%), Survey 8: 9–13 July (n = 1001, RR = 12.5%), Survey 9: 7–11 January 2022 (n = 1004, RR = 10.3%). Table S1 in the Supplement provides details of the response rate calculations and survey interview information. A total of 9011 participants were analyzed in this study.

2.2. Measures

Alcohol–cannabis co-use was measured by combining the responses to two distinct questions on substance use. (1) “During the past seven days, on how many days did you use alcohol?” and (2) “During the past seven days, on how many days did you use cannabis?”. Response categories for each question were recoded to reflect use on at least one day (coded 1) versus use on 0 days (coded 0). Participants who reported using alcohol on at least one day and who also reported using cannabis on at least one day were classified as engaging in alcohol and cannabis co-use in the past week. The co-use binary variable, which reflects the use of alcohol and cannabis, was coded 1 if they used both substances at least once in the past week and 0 otherwise.
Anxiety was measured by the Generalized Anxiety Disorder (GAD-7) scale [34]. The GAD-7 includes seven items using a four-point metric, ranging from 0 = “not at all” to 3 = “nearly every day.” The total score ranged from 0 to 21, with higher scores reflecting more severe functional impairments because of anxiety. Participants with a score ≥ 10 (cut-off) were defined as experiencing moderate to severe anxiety [35,36,37,38].
Depression was measured by a single question from the Center for Epidemiologic Studies Depression Scale (CES-D) [39]: “In the past 7 days, how often have you felt depressed?” Response categories were “rarely or none of the time (less than 1 day)”, “some or a little of the time (1–2 days)”, “occasionally or a moderate amount of the time (3–4 days)”, and “most or all of the time (5–7 days)”. Those who reported feeling depressed 3–4 or 5–7 days were identified as experiencing depressive symptoms [39]. A cut-off of 3 days of feeling depressed in 7 days was used to identify individuals experiencing depression.
Loneliness was measured with a single item from the CES-D [39]. This item asked participants, “In the past 7 days, how often have you felt lonely?” with the following response options: “rarely or none of the time (less than 1 day)”, “some or a little of the time (1–2 days)”, “occasionally or a moderate amount of the time (3–4 days)”, and “most or all of the time (5–7 days)” [39]. Participants were considered lonely if they reported feeling lonely for 3–4 or 5–7 days. A cut-off of 3 days of feeling lonely within 7 days was applied to identify individuals experiencing loneliness.
Heavy episodic drinking (HED) was assessed using the question: “On how many of the past seven days did you drink five/four or more drinks on one occasion?” Heavy episodic drinkers were defined as the consumption of 5 or more standard drinks (≥68.0 g of alcohol) for cisgender men and transgender and gender diverse (TGD) participants and 4 or more standard drinks (≥54.4 g of alcohol) for cisgender women [40,41].

2.3. Covariates

Sociodemographic covariates included gender (cisgender men, cisgender women, and TGD), age (18–39, 40–59 and 60+ years), ethno-racial background (White and Non-white (i.e., Asian/Black/Indigenous/Arab/Latinx and other ethnicities)), marital status (married/living with a partner, separated/divorced/widowed, single and marital status not stated), and residential environment (urban, suburban, and rural). Note that the gender identity question had the following response options: “Man,” “Woman,” “Transgender man,” “Transgender woman,” “Two-Spirit,” “Non-binary (genderqueer, gender fluid),” “Questioning/Not sure of my gender identity,” “Identity not listed,” and “Prefer not to answer.” Individuals who self-identified as transgender, two-spirit, or non-binary and those who selected “Questioning/Not sure of my gender identity” or did not find their gender listed were categorized as TGD. We excluded participants who responded “prefer not to answer” from the main analysis (i.e., 21 participants).
Additional covariates included socioeconomic status measured by household income (less than $40,000 as the reference category, $40,000–$79,999, $80,000–$119,999, $120,000 or more, and income not stated), educational attainment (post-secondary as the reference category, high school diploma or less, college degree/diploma, university degree/diploma, and education attainment not stated), and employment status during COVID-19 (employed (no change due to the pandemic) as the reference category, unemployed (no change due to the pandemic), and other impacts on employment (i.e., participants working from home due to the pandemic and returning to their usual workplace or participants who were unemployed/laid off/let go due to the pandemic who were back working with the same or a new employer).

2.4. Statistical Analyses

We calculated the prevalence of the use of alcohol only, cannabis only, co-use and no-use of both substances by sociodemographic characteristics. We performed multivariate logistic regressions on the pooled data from May 2020 to January 2022 to assess (i) the sociodemographic risk factors for alcohol–cannabis co-use, and (ii) associations of mental health symptoms and HED with co-use during the pandemic. To evaluate the risk factors, four multivariate logistic regression analyses were conducted to compare alcohol–cannabis co-use with: (1) non-co-use of both substances, (2) use of alcohol only (i.e., alcohol use and no cannabis use), (3) use of cannabis only (i.e., cannabis use and no alcohol use), and 4) no use of either substance. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were provided for each regression analysis. We also reported average marginal effects for the main analyses in the Supplement, as well as some results of interaction analysis. All analyses were performed using Stata version 16.1 (StataCorp, College Station, TX, USA).

3. Results

3.1. Description of Participants and Prevalence of Alcohol–Cannabis Co-Use

Table 1 shows study respondents’ sociodemographic characteristics and substance use prevalence across socio-demographic groups. Most of the 9011 participants were White (68.9%), married (62.5%), employed (85.0%), and had a university degree (52.2%). Approximately 48% of participants reported drinking alcohol only (without cannabis); 3.1% used only cannabis, and 10.1% used alcohol and cannabis during the past week. The prevalence of co-use was higher among individuals aged 18–39 years (14.5%), unemployed individuals (13.3%), individuals with a high household income of $80,000–$119,000 (12.8%), higher among TGD people (35.5%) followed by cisgender men (11.9%), individuals living in an urban area (11.0%), and individuals with less than a university degree (10.5–11.9%).

3.2. Associations of Sociodemographic Factors with Alcohol–Cannabis Co-Use

Table 2 shows the results of logistic regressions between sociodemographic characteristics and alcohol–cannabis co-use. Comparing co-use and non-co-use, TGD people (aOR = 3.61, 95% CI 2.09–6.25 representing an 11% increase in the likelihood of alcohol-cannabis co-use—detailed results in Table S2 in the Supplement), people who were separated/divorced/widowed (aOR = 1.60, 95% CI 1.23–2.07), people living in urban areas (aOR = 1.26, 95% CI 1.07–1.56), and people with a high household income of $80,000–$119,000 (aOR = 1.41, 95% CI 1.09–1.82) were at greater odds of reporting co-use of alcohol and cannabis during the pandemic compared to men, single individuals, people living in rural areas, and those with income less than $40,000., respectively. However, women (aOR = 0.63, 95%CI 0.55–0.73), people aged 40–59 years (aOR = 0.53, 95% CI 0.45–0.63) and 60+ (aOR = 0.27, 95% CI 0.22–0.33 or a decrease of 11% on the probability of co-use), and non-White people (i.e., Asian/Black/Indigenous/Arab/Latinx and other ethnicities) (aOR = 0.77, 95% CI 0.66–0.91), unemployed individuals (aOR = 0.74, 95%CI 0.59–0.92) and those with university degree (aOR = 0.67, 95%CI 0.54–0.82) were at lower odds of reporting alcohol–cannabis co-use during the pandemic compared to men, younger adults, white people, employed individuals, and people with high school diploma, respectively. These results are generally qualitatively similar to those obtained when the co-users group was compared to the alcohol only users, cannabis only users and non-users groups.
To assess the temporal trend and how associations between alcohol-cannabis co-use and age group may change over the course of the pandemic, we added an interaction term between age group and survey waves in the regression. The results are presented in Table S3 in the Supplement. The joint test of significance for the Wave binary variables displayed a p-value greater than 0.05, suggesting no temporal effect. Similar results were found for age groups and interaction terms with Waves, indicating no differential impact over time across age groups.

3.3. Associations with Heavy Episodic Drinking, Anxiety, Depression, and Loneliness

Table 3 shows the results of multivariate logistic regressions of co-use on self-reported: anxiety, depression, loneliness, and HED (controlling for sociodemographic characteristics). Alcohol–cannabis co-use (vs. non co-use) was strongly associated with self-reported HED (aOR = 7.58, 95% CI 6.50–8.84 or an 34% increase in the likelihood of engaging in HED—detailed results in Table S4 in the Supplement), anxiety (aOR = 1.93, 95% CI 1.65–2.25 or an 10% increase in the likelihood of experiencing anxiety), depression (aOR = 1.96, 95% CI 1.67–2.29 or an 10% increase in the likelihood of experiencing depression), and loneliness (aOR = 1.87, 95% CI 1.60–2.19 or an 10% increase in the likelihood of experiencing loneliness). Being a woman, TGD, and unemployed increased the likelihood of reporting anxiety, depression, and loneliness. Those who were separated/divorced/widowed, had a household income higher than $40,000, and unemployed were more likely to report heavy alcohol drinking.
To evaluate whether the relationship between co-use of substances and mental health outcomes varies by age and gender, interaction terms were included in the model. Specifically, these terms examined the interactions between co-use and age groups, as well as co-use and gender. The complete results are presented in Table S5 of the Supplement. For anxiety, depression, and loneliness, the findings indicate that the associations between co-use and these mental health outcomes did not significantly differ among various age groups or between genders. However, the odds of women who co-use alcohol and cannabis engaging in HED were 5.49 times higher than those for men co-using both substances. Additionally, individuals aged 60 and older who co-use alcohol and cannabis are 3.97 times more likely to engage in HED compared to those aged 18–39 who co-use both substances.

4. Discussion

The present study aimed to assess the prevalence of alcohol–cannabis co-use during the pandemic across sociodemographic groups and identify risk factors of co-use in Canadian adults. We also examined the associations of co-use of these substances with mental health symptoms and HED.

4.1. Prevalence and Sociodemographic Risk Factors of Alcohol–Cannabis Co-Use

We found that the prevalence of alcohol–cannabis co-use during the pandemic varied across sociodemographic characteristics—it was notably higher among TGD people and cisgender men, people aged 18–39 years, unemployed people, individuals living in urban areas, and those with high household income ($80,000–$119,000). Additionally, the multivariate logistic regression results revealed that TGD people (vs cisgender men), people living in urban areas (vs rural areas), people who were separated/divorced/widowed (vs single), and people with high household income (vs less than $40,000) were more likely to report alcohol–cannabis co-use in the past week. In addition, we found that co-users of alcohol and cannabis were more likely to report anxiety, depression, loneliness and heavy episodic drinking.
The high prevalence of co-use of substances among TGD participants compared to cisgender participants (almost 3 times higher relative to cisgender men and more than 4 times higher relative to cisgender women) is in line with the literature on substance use among TGD people. Previous studies have indicated that TGD people have high rates of alcohol use, cannabis use, illicit drug use, and non-medical use of prescription drugs compared with cisgender people [32,42,43,44,45]. Other research has indicated that TGD people were also more likely than cisgender men to co-use alcohol and cannabis during the COVID-19 pandemic, potentially due to increased psychological distress [46,47]. The increase in psychological distress among TGD individuals may be due to the interruption of gender-affirming treatments in Canada during the pandemic. These treatments are known to help alleviate gender dysphoria, which is the distress some TGD individuals feel when their gender identity does not match the sex assigned at birth. However, during the pandemic, these treatments were delayed or put on hold to prioritize medical resources for the increasing number of COVID-19 patients.
Our findings replicate previous results showing that the odds of co-use are higher among cisgender men and those of a younger age group [17,29,48,49]. For example, studies on college-aged drinkers in the US showed that the use of cannabis increased with the level of alcohol consumption [50,51]. We also identified several protective factors for co-using alcohol and cannabis that were found in some studies: women, non-White (i.e., Asian/Black/Indigenous/Arab/Latinx and other ethnicities), and unemployed [27,28,52]. Other socio-demographic correlates of alcohol–cannabis co-use, such as being separated/divorced/widowed, found in this study, were also identified in the literature [29,53,54,55].

4.2. Co-Use Associations with HED, Anxiety, Depression and Loneliness

The relationship between alcohol–cannabis co-use and HED, anxiety, and depression is consistent with the literature as well [16,20,29,48]. Co-users were at over 7 times greater odds of engaging in HED than those who did not co-use both substances. This result is in line with the findings from a large-scale longitudinal survey data from the US that found that most co-users of alcohol and cannabis were more likely to report heightened HED behaviour and depression [10,19,29]. This suggests that co-users might experience more problems from drinking during the pandemic, such as alcohol dependence and negative alcohol-related consequences like risky driving and mental health problems [29,56]. These results, coupled with the fact that the odds of alcohol–cannabis co-use are higher in younger adults and the TGD population, reflect a clinical population in which younger and TGD people may need treatment for both substances.
We also found that co-users of alcohol and cannabis are more likely to report loneliness. A similar result was found in the literature during and after the pandemic [22,57], suggesting that alcohol and cannabis may be used together to cope following a traumatic event, such as the COVID-19 restrictions on vulnerable individuals [58]. These associations are concerning because loneliness has increased among the general population during the pandemic, and evidence suggests that loneliness is associated with poor physical and mental health outcomes, including lower quality of life, increased suicidality, and increased substance use severity [57,59]. This shows that interventions to reduce loneliness may help improve population health and well-being and prevent or reduce alcohol and cannabis co-use.
Our findings indicate that alcohol–cannabis co-use is associated with higher self-reported anxiety and depression. This conclusion aligns with findings in the literature, where many individuals turned to these substances to cope with the overwhelming stress caused by social distancing measures during the COVID-19 pandemic [58]. The measures began in Canada with the declaration of a state of emergency at the start of the first wave of the pandemic in March 2020. This was followed by social distancing measures that included prohibiting large gatherings, implementing stay-at-home orders, closing schools, and restricting restaurants and bars until December 2021 in most provinces. Public health restriction policies varied across Canadian provinces and territories, depending on the daily counts of new COVID-19 cases. Between November and December 2020, several provinces introduced stricter public health restrictions, which included limiting retail capacity, closing non-essential businesses, and suspending sports and recreational programs. Alberta and Ontario implemented lockdowns in December 2020, while Quebec enforced curfews (between 8 p.m. and 5 a.m.) throughout 2021 in regions experiencing significant outbreaks. However, the survey was not designed to allow provincial-level analysis, which prevented us from accounting for these variations across provinces in our analysis. These restrictions have contributed to an increase in mental health problems among the population. It is crucial to recognize the risks associated with the co-use of alcohol and cannabis during a crisis, as well as the urgent need for practical support strategies during difficult times.

4.3. Limitations

There are limitations to this study. First, the use of a survey panel and reliance on participants from the English-speaking population (thus excluding French-speaking Canadians) may lead to participation and selection biases [60], impacting prevalence estimates. Second, the non-probability sampling method, combined with the web-based survey format, may introduce selection bias, as it only reaches literate individuals who have internet access and are sufficiently interested in the topic to complete the survey. As a result, the findings may not be applicable to the entire Canadian population. Third, the way gender identity was measured in this survey might have influenced the number of respondents identifying as TGD. The options provided for the gender identity question may not include all possible identities. Experts suggest adding a second question regarding sex assigned at birth, offering choices of “male” or “female” [61,62] to correctly identify and classify TGD individuals, which was not done in this study. This may result in misclassification regarding gender identity. Misclassification may also occur when participants who selected: “Questioning/Not sure of my gender identity” and “Identity not listed” were included in the TGD group. Additionally, we had to group various gender identities into TGD due to small sample sizes; thus, potential differences in co-use among various TGD groups could not be examined. Fourth, the study is cross-sectional. As a result, we cannot draw causal inferences or address issues of temporality. Additionally, we were unable to study the same individuals over time to see if their behaviour changed. Fifth, the survey did not include questions on participants’ clinical histories or whether they had undergone pharmacological treatments; these factors could affect the study outcomes and introduce bias. Finally, all data in this study are based on self-reported responses, which may suffer from recall bias [63,64].

5. Conclusions

Around 10% of participants co-used alcohol and cannabis, with individuals who were TGD and young adults being significantly more likely to co-use alcohol and cannabis. Additionally, co-using cannabis and alcohol increased the likelihood of self-reported HED, anxiety, depression and loneliness, which may lead to mental health and/or alcohol use disorders [16]. These findings support the need for programs to prevent and treat both alcohol and cannabis use problems, rather than focusing on a single behaviour, particularly in vulnerable populations identified, i.e., TGD, and young adult populations.
An equitable and inclusive approach is essential for designing and implementing measures to reduce disease propagation during major public health crises, such as limiting access to non-essential health services (e.g., gender-affirming treatments). While these measures are necessary, the needs of minority and more vulnerable groups must be considered through an approach that can help anticipate and mitigate potential negative impacts that may drive vulnerable individuals towards unhealthy behaviours, exacerbating their already precarious situations. A continuous evaluation of the effects of lockdown rules and social distancing (related to the pandemic) on unhealthy behaviours among at-risk populations may help inform targeted health promotion strategies for future public health crises. We recommend that future studies utilize a longitudinal approach to assess the causal effects of alcohol-cannabis co-use on mental health and HED. This approach will help us understand how it affects individuals over time, providing better information for policy development. Additionally, we suggest including a two-step gender identity question to more accurately identify individuals’ gender, as well as incorporating questions about participants’ clinical histories to ensure more robust findings.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/psychoactives4030027/s1, Table S1: Survey interview information and response rate calculations; Table S2: Average marginal effects of covariates on the probability of alcohol-cannabis co-use during the pandemic; Table S3: Associations of sociodemographic factors with the alcohol–cannabis co-use with survey wave and age group interactions terms and temporal trend testing; Table S4: Average marginal effects of covariates on the probability of experiencing a mental health problem during the pandemic; Table S5: Testing interaction effects of Alcohol-cannabis co-use with gender and age on heavy episodic drinking and mental health symptoms.

Author Contributions

Conceptualization, N.H.S., H.A.H., K.D.S., Y.T.N., T.E.-M., J.R., S.W., S.I., S.A., and C.d.O.; Methodology, N.H.S., H.A.H., T.E.-M., and C.d.O.; Validation, N.H.S., H.A.H., K.D.S., Y.T.N., T.E.-M., J.R., S.W., S.I., S.A. and C.d.O.; Formal Analysis, N.H.S.; Data Curation, N.H.S.; Writing—Original Draft Preparation, N.H.S.; Writing—Review & Editing, N.H.S., H.A.H., K.D.S., Y.T.N., T.E.-M., J.R., S.W., S.I., S.A. and C.d.O.; Supervision, H.A.H., S.W. and C.d.O.; Project Administration, H.A.H. and T.E.-M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki, and approved by the Centre for Addiction and Mental Health Research Ethics Board (protocol code 051/2020 approved on 28 April 2020).

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

All data generated or analyzed during this study are publicly available for download at: http://www.delvinia.com/coronavirus (accessed on 5 May 2025).

Acknowledgments

Delvinia, a research technology firm, provided in-kind support for data collection. We did not receive funding from Delvinia; however, they administered our questionnaires to Canadians through their web-based panel, AskingCanadians (http://www.delvinia.com/solutions/askingcanadians (accessed on 5 May 2025)), without charging fees. The authors acknowledge Delvinia’s in-kind support for data collection.

Conflicts of Interest

The authors declare that there are no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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Table 1. Sociodemographic characteristics of respondents and prevalence of alcohol, cannabis, and co-use across socio-demographic groups.
Table 1. Sociodemographic characteristics of respondents and prevalence of alcohol, cannabis, and co-use across socio-demographic groups.
Total SampleAlcohol OnlyCannabis OnlyCo-Use No-Use
n%n (%)n (%)n (%)n (%)
Total, n (%)   90111004353 (48.3)280 (3.1)907 (10.1)3471 (38.5)
Gender   
Man   445649.52247 (50.4)137 (3.1)529 (11.9)1543 (34.6)
Woman   447249.62087 (46.7)139 (3.1)356 (8.0)1890 (42.3)
Transgender and gender-diverse620.715 (24.2)4 (6.4)22 (35.5)21 (33.9)
Prefer not to answer210.24 (19.1)0 (0)0 (0.0)17 (80.9)
Age   
Age 18–39   346738.51433 (41.3)162 (4.7)501 (14.5)1371 (39.5)
Age 40–59   284631.61377 (48.4)82 (2.9) 264 (9.3)1123 (39.5)
Age 60+    269829.91543 (57.2)36 (1.3)142 (5.3)977 (36.2)
Ethno-racial background
White   620968.93339 (53.8)197 (3.2)619 (10.0)2054 (33.1)
Non-white   280231.11014 (36.2)83 (3.0)288 (10.3)1417 (50.6)
Marital status   
Separated/divorced/widowed112612.5517 (45.9)30 (2.7)111 (9.9)468 (41.6)
Married   563162.52953 (52.4)147 (2.6)550 (9.8)1981 (35.2)
Single   213523.7841 (39.4)100 (4.7)233 (10.9)961 (45.0)
Marital status not stated1191.342 (35.3)3 (2.5)13 (10.9)61 (51.3)
Residential environment
Urban   422446.91955 (46.3)134 (3.2)466 (11.0)1669 (39.5
Suburban   335637.21714 (51.1)93 (2.8)318 (9.5)1231 (36.7)
Rural   143115.9684 (47.8)53 (3.7)123 (8.6)571 (39.9)
Income   
Income less than $40,000108012.0346 (32.0)51 (4.7)108 (10.0)575 (53.2)
Income of $40,000–$79,999221624.6980 (44.2)91 (4.1)255 (11.5)890 (40.2)
Income of $80,000–$119,999203122.51026 (50.5)55 (2.7)259 (12.8)691 (34.0)
Income $120,000+223824.81280 (57.2)45 (2.0)219 (9.8)694 (31.0)
Income not stated144616.0721 (49.9)38 (2.6)66 (4.6)621 (42.9)
Employment status
Employed   766085.03764 (49.1)229 (3.0)737 (9.6)2930 (38.2)
Unemployed   8679.6384 (44.3)38 (4.4)115 (13.3)330 (38.1)
Other impact on employment4845.4205 (42.4)13 (2.7)55 (11.4)211 (43.6)
Educational attainment
Post-secondary   136215.1610 (44.8)58 (4.3)155 (11.4)539 (39.6)
High school   106811.9440 (41.2)48 (4.5)112 (10.5)468 (43.8)
College   180220.0840 (46.6)71 (3.9)214 (11.9)677 (37.6)
University   470352.22438 (51.8)102 (2.2)420 (8.9)1743 (37.1)
Education attainment not stated760.825 (32.9)1 (1.3)6 (7.9)44 (57.9)
Table 2. Associations of sociodemographic factors with alcohol–cannabis co-use during the pandemic.
Table 2. Associations of sociodemographic factors with alcohol–cannabis co-use during the pandemic.
Co-Use vs. Non Co-Use Co-Use vs. Alcohol Use OnlyCo-Use vs. Cannabis Use OnlyCo-Use vs. No-Use
aOR (95% CI)aOR (95% CI)aOR (95% CI)aOR (95% CI)
Gender
Women0.63 *** (0.55–0.73)0.71 *** (0.61–0.83)0.74 ** (0.55–0.99)0.54 *** (0.46–0.63)
TGD3.61 *** (2.09–6.25)4.73 *** (2.36–9.49)1.72 (0.56–5.27)3.42 *** (1.81–6.46)
Age
Age 40–590.53 *** (0.45–0.63)0.51 *** (0.42–0.61)1.10 (0.79–1.52)0.54 *** (0.45–0.65)
Age 60+0.27 *** (0.22–0.33)0.23 *** (0.18–0.29)1.44 (0.91–2.28)0.30 *** (0.24–0.37)
Ethno-racial background
Non-White0.77 *** (0.66–0.91)1.10 (0.92–1.30)1.07 (0.78–1.47)0.48 *** (0.41–0.58)
Marital status
Separated/divorced/widowed1.60 *** (1.23–2.07)1.46 *** (1.10–1.94)1.77 ** (1.07–2.95)1.59 *** (1.20–2.11)
Married1.19 (1.00–1.42)1.08 (0.89–1.31)1.44 ** (1.04–1.99)1.34 *** (1.11–1.62)
Marital status not stated1.85 (0.96–3.57)2.25 ** (1.07–4.74)2.21 (0.54–9.09)1.87 (0.91–3.84)
Living area
Urban1.26 ** (1.01–1.56)1.11 (0.88–1.40)1.37 (0.91–2.06)1.40 *** (1.11–1.78)
Suburban1.07 (0.85–1.34)0.92 (0.72–1.17)1.38 (0.91–2.10)1.21 (0.95–1.55)
Income
Income: $40,000–$79,9991.24 (0.97–1.59)0.91 (0.69–1.20)1.32 (0.86–2.03)1.51 *** (1.17–1.96)
Income: $80,000–$119,9991.41 *** (1.09–1.82)0.93 (0.70–1.23)2.06 *** (1.28–3.32)1.89 *** (1.44–2.48)
Income: $120,000+1.06 (0.81–1.38)0.65 *** (0.48–0.87)2.01 *** (1.20–3.37)1.59 *** (1.20–2.12)
Income not stated0.51 *** (0.36–0.71)0.35 *** (0.25–0.51)0.78 (0.45–1.35)0.64 ** (0.45–0.90)
Employment
Unemployed0.74 *** (0.59–0.92)0.79 ** (0.62–1.00)0.96 (0.63–1.46)0.69 *** (0.54–0.88)
Other impacts on employment1.04 (0.73–1.49)1.15 (0.78–1.70)1.46 (0.70–3.03)0.90 (0.61–1.33)
Educational attainment
High school0.96 (0.73–1.25)1.00 (0.75–1.33)0.95 (0.59–1.53)0.89 (0.67–1.18)
College1.01 (0.81–1.27)0.97 (0.76–1.24)1.19 (0.78–1.81)1.06 (0.83–1.36)
University0.67 *** (0.54–0.82)0.58 *** (0.46–0.72)1.48 (1.00–2.20)0.75 ** (0.60–0.95)
Education attainment not stated0.85 (0.33–2.17)0.84 (0.30–2.36)2.73 (0.27–27.93)0.77 (0.28–2.1)
Survey waves
Wave 21.14 (0.84–1.56)1.07 (0.77–1.49)1.02 (0.56–1.87)1.26 (0.90–1.76)
Wave 31.27 (0.93–1.72)1.20 (0.86–1.65)1.74 (0.90–3.35)1.37 (0.98–1.91)
Wave 41.28 (0.94–1.74)1.18 (0.85–1.63)1.25 (0.67–2.31)1.43 ** (1.02–1.99)
Wave 51.17 (0.85–1.60)1.19 (0.85–1.67)1.36 (0.72–2.56)1.11 (0.79–1.56)
Wave 61.43 ** (1.06–1.93)1.48 ** (1.07–2.04)0.82 (0.46–1.44)1.44 ** (1.04–2.00)
Wave 71.31 (0.97–1.78)1.38 (0.99–1.91)1.06 (0.58–1.94)1.32 (0.95–1.84)
Wave 81.09 (0.80–1.50)1.05 (0.75–1.46)1.01 (0.55–1.87)1.20 (0.86–1.69)
Wave 91.32 (0.97–1.80)1.29 (0.93–1.79)0.82 (0.46–1.47)1.43 ** (1.02–1.99)
Constant0.21 *** (0.14–0.33)0.65 (0.41–1.03)1.03 (0.46–2.31)0.39 *** (0.25–0.63)
Observations8990525611874361
Pseudo R-squared0.060.080.050.08
Goodness-of-fit (Hosmer–Lemeshow), Chi 2 (p value)7.10 (0.53)7.40 (0.50)11.66 (0.17)8.36 (0.40)
Legend: *** and ** Odds ratios are significant at the 1% and 5% significance level, respectively. 95% confidence intervals in parentheses. Reference categories: Gender (Men), Age (18–39), Ethno-racial background (White), Marital status (Single), Living area (Rural), Income (less than $40,000), Employment (Employed), Educational attainment (Post-secondary), Survey waves (Wave 1).
Table 3. Associations of co-use of alcohol with heavy episodic drinking and mental health symptoms.
Table 3. Associations of co-use of alcohol with heavy episodic drinking and mental health symptoms.
AnxietyDepressionLonelinessHeavy Episodic Drinking
Alcohol–cannabis co-use1.93 ***1.96 ***1.87 ***7.58 ***
(1.65–2.25)(1.67–2.29)(1.60–2.19)(6.50–8.84)
Gender
Women1.42 ***1.37 ***1.34 ***0.78 ***
(1.28–1.59)(1.23–1.53)(1.20–1.49)(0.70–0.87)
Transgender and gender-diverse2.06 ***2.72 ***2.31 ***0.87
(1.21–3.50)(1.61–4.60)(1.37–3.92)(0.48–1.59)
Age
Age 40–590.78 ***1.000.83 ***1.03
(0.69–0.88)(0.88–1.13)(0.74–0.95)(0.91–1.17)
Age 60+0.34 ***0.45 ***0.45 ***0.71 ***
(0.29–0.40)(0.39–0.53)(0.39–0.53)(0.61–0.82)
Ethno-racial background
Non White1.15 **1.011.040.93
(1.02–1.29)(0.89–1.13)(0.92–1.17)(0.83–1.05)
Marital status
Separated/divorced/widowed1.121.071.21 **1.22 **
(0.92–1.36)(0.89–1.29)(1.01–1.44)(1.01–1.48)
Married1.040.86 **0.50 ***1.07
(0.91–1.18)(0.75–0.97)(0.44–0.56)(0.94–1.22)
Living area
Urban1.131.121.020.96
(0.96–1.33)(0.95–1.32)(0.87–1.19)(0.83–1.12)
Suburban1.071.030.941.01
(0.91–1.26)(0.87–1.22)(0.80–1.11)(0.87–1.18)
Income
Income: $40,000–$79,9990.77 ***0.68 ***0.74 ***1.36 ***
(0.64–0.91)(0.58–0.81)(0.62–0.87)(1.13–1.63)
Income: $80,000–$119,9990.63 ***0.56 ***0.75 ***1.34 ***
(0.52–0.76)(0.46–0.67)(0.62–0.89)(1.10–1.62)
Income: $120,000+0.57 ***0.42 ***0.51 ***1.53 ***
(0.47–0.69)(0.34–0.51)(0.42–0.62)(1.25–1.86)
Income not stated0.57 ***0.58 ***0.58 ***1.01
(0.47–0.70)(0.47–0.70)(0.48–0.71)(0.82–1.25)
Employment
Unemployed1.81 ***1.74 ***1.68 ***1.31 ***
(1.55–2.13)(1.48–2.05)(1.43–1.97)(1.11–1.55)
Other impacts on employment1.241.231.211.05
(0.99–1.55)(0.98–1.55)(0.96–1.51)(0.84–1.32)
Educational attainment
Post-secondary1.29 **1.211.060.97
(1.05–1.58)(0.99–1.48)(0.87–1.29)(0.80–1.18)
College1.141.020.940.96
(0.94–1.38)(0.84–1.24)(0.78–1.13)(0.80–1.16)
University1.101.040.970.89
(0.92–1.31)(0.87–1.23)(0.82–1.14)(0.75–1.05)
Wave 20.811.081.051.03
(0.66–1.01)(0.87–1.36)(0.85–1.31)(0.83–1.28)
Wave 30.72 ***0.900.901.15
(0.58–0.89)(0.72–1.13)(0.72–1.12)(0.93–1.43)
Wave 40.72 ***0.951.061.19
(0.58–0.90)(0.75–1.19)(0.85–1.32)(0.96–1.47)
Wave 50.841.140.901.13
(0.67–1.04)(0.91–1.43)(0.72–1.13)(0.91–1.40)
Wave 60.991.161.091.06
(0.80–1.22)(0.93–1.45)(0.88–1.36)(0.86–1.32)
Wave 70.821.050.951.07
(0.66–1.01)(0.84–1.31)(0.76–1.18)(0.86–1.33)
Wave 80.73 ***0.950.80 *1.19
(0.58–0.91)(0.76–1.20)(0.64–1.00)(0.96–1.48)
Wave 91.041.201.141.04
(0.84–1.28)(0.96–1.49)(0.91–1.41)(0.83–1.29)
Constant0.36 ***0.34 ***0.59 ***0.23 ***
(0.27–0.49)(0.25–0.46)(0.45–0.79)(0.17–0.32)
Observations8990899089908976
Pseudo R-squared0.060.060.080.09
Goodness-of-fit (Hosmer–Lemeshow), Chi 2 (p value)5.74 (0.68)13.06 (0.11)8.37 (0.40)9.69 (0.29)
Legend: *** and ** Odds ratios are significant at the 1% and 5% significance level, respectively. 95% confidence intervals in parentheses. Reference categories: Non-co-use, Gender (Men), Age (18–39), Ethno-racial background (White), Marital status (Single), Living area (Rural), Income (less than $40,000), Employment (Employed), Educational attainment (Post-secondary), Survey waves (Wave 1).
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MDPI and ACS Style

Somé, N.H.; Imtiaz, S.; Nigatu, Y.T.; Wells, S.; de Oliveira, C.; Ali, S.; Elton-Marshall, T.; Rehm, J.; Shield, K.D.; Hamilton, H.A. Co-Use of Alcohol and Cannabis During COVID-19: Associations Between Sociodemographic Factors and Self-Reported Mental Health Symptoms and Heavy Episodic Drinking in Canadian Adults. Psychoactives 2025, 4, 27. https://doi.org/10.3390/psychoactives4030027

AMA Style

Somé NH, Imtiaz S, Nigatu YT, Wells S, de Oliveira C, Ali S, Elton-Marshall T, Rehm J, Shield KD, Hamilton HA. Co-Use of Alcohol and Cannabis During COVID-19: Associations Between Sociodemographic Factors and Self-Reported Mental Health Symptoms and Heavy Episodic Drinking in Canadian Adults. Psychoactives. 2025; 4(3):27. https://doi.org/10.3390/psychoactives4030027

Chicago/Turabian Style

Somé, Nibene H., Sameer Imtiaz, Yeshambel T. Nigatu, Samantha Wells, Claire de Oliveira, Shehzad Ali, Tara Elton-Marshall, Jürgen Rehm, Kevin D. Shield, and Hayley A. Hamilton. 2025. "Co-Use of Alcohol and Cannabis During COVID-19: Associations Between Sociodemographic Factors and Self-Reported Mental Health Symptoms and Heavy Episodic Drinking in Canadian Adults" Psychoactives 4, no. 3: 27. https://doi.org/10.3390/psychoactives4030027

APA Style

Somé, N. H., Imtiaz, S., Nigatu, Y. T., Wells, S., de Oliveira, C., Ali, S., Elton-Marshall, T., Rehm, J., Shield, K. D., & Hamilton, H. A. (2025). Co-Use of Alcohol and Cannabis During COVID-19: Associations Between Sociodemographic Factors and Self-Reported Mental Health Symptoms and Heavy Episodic Drinking in Canadian Adults. Psychoactives, 4(3), 27. https://doi.org/10.3390/psychoactives4030027

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