Recreational cannabis legalization and alcohol purchasing: a difference-in-differences analysis

Association between non-medical cannabis legalization and alcohol sales: Quasi-experimental evidence from Canada

BACKGROUND

There is increasing interest in understanding the impact of non-medical cannabis legalization on use of other substances, especially alcohol. Evidence on whether cannabis is a substitute or complement for alcohol is both mixed and limited. This study provides the first quasi-experimental evidence on the impact of Canada's legalization of non-medical cannabis on beer and spirits sales.

METHODS

We used the interrupted time series design and monthly data on beer sales between January 2012 and February 2020 and spirits sales between January 2016 and February 2020 across Canada to investigate changes in beer and spirits sales following Canada's cannabis legalization in October 2018. We examined changes in total sales, nationally and in individual provinces, as well as changes in sales of bottled, canned and kegged beer.

RESULTS

Canada-wide beer sales fell by 96 hectoliters per 100,000 population (p=0.011) immediately after non-medical cannabis legalization and by 4 hectoliters per 100,000 population (p>0.05) each month thereafter for an average monthly reduction of 136 hectoliters per 100,000 population (p<0.001) post-legalization. However, the legalization was associated with no change in spirits sales. Beer sales reduced in all provinces except the Atlantic provinces. By beer type, the legalization was associated with declines in sales of canned and kegged beer but there was no reduction in sales of bottled beer.

CONCLUSIONS

Non-medical cannabis legalization was associated with a decline in beer sales in Canada, suggesting substitution of non-medical cannabis for beer. However, there was no change in spirits sales following the legalization.

The Impact of Cannabis Decriminalization and Legalization on Road Safety Outcomes: A Systematic Review

INTRODUCTION

There is substantial debate concerning the impact of cannabis decriminalization and legalization on road safety outcomes.

METHODS

Seven databases were systematically searched: Embase, MEDLINE, and PsycINFO through Ovid as well as Web of Science Core Collection, SafetyLit, Criminal Justice Database (ProQuest), and Transport Research International Documentation (from inception to June 16, 2021). Eligible primary studies examined group-level cannabis decriminalization or legalization and a road safety outcome in any population.

RESULTS

A total of 65 reports of 64 observational studies were eligible, including 39 that applied a quasi-experimental design. Studies examined recreational cannabis legalization (n=50), medical cannabis legalization (n=22), and cannabis decriminalization (n=5). All studies except 1 used data from the U.S. or Canada. Studies found mixed impacts of legalization on attitudes, beliefs, and self-reported driving under the influence. Medical legalization, recreational legalization, and decriminalization were associated with increases in positive cannabis tests among drivers. Few studies examined impacts on alcohol or other drug use, although findings suggested a decrease in positive alcohol tests among drivers associated with medical legalization. Medical legalization was associated with reductions in fatal motor-vehicle collisions, whereas recreational legalization was conversely associated with increases in fatal collisions.

DISCUSSION

Increased cannabis positivity may reflect changes in cannabis use; however, it does not in itself indicate increased impaired driving. Subgroups impacted by medical and recreational legalization, respectively, likely explain opposing findings for fatal collisions. More research is needed concerning cannabis decriminalization; the impacts of decriminalization and legalization on nonfatal injuries, alcohol and other drugs; and the mechanisms by which legalization impacts road safety outcomes.

Relationship perceptions and conflict behavior among cannabis users

BACKGROUND

Cannabis use is increasingly common, yet few studies have examined its associations with couple functioning. To address this gap, we used actor-partner interdependence modeling to examine the associations between cannabis use, relationship perceptions, and observed conflict behavior in a community-based sample of cannabis users and their partners.

METHODS

Cannabis users (N = 232; 96 males; 122 females; 14 undisclosed biological sex) and their partners completed self-reports of cannabis frequency and global relationship satisfaction and commitment. At a laboratory visit, couples engaged in a 10 min conflict discussion and a 5 min discussion of areas of agreement, and reported on their post-conflict perceptions. Each partner's parasympathetic activity was assessed during the conflict task, and trained raters coded conflict and recovery behavior RESULTS: More frequent actor cannabis use was associated with more negative engagement and avoidance behavior during conflict, less parasympathetic withdrawal during conflict, and less effective behavioral recovery immediately after conflict. More frequent cannabis use was also associated with greater satisfaction with conflict resolution following the conflict discussion, but was not associated with perceived overall relationship satisfaction or commitment. Cannabis effects were independent of alcohol use CONCLUSIONS: Among cannabis users, there are discrepancies between perceived and objective measures of relationship functioning, such that cannabis users viewed their relationships as better functioning compared to independent raters' reports. These findings highlight the need for a nuanced understanding of the associations between cannabis and relationship functioning, which appear to be distinct from alcohol, as well as an organizing theoretical framework to stimulate future research.

Changes in alcohol use by cannabis use status among adolescents and young adults in the United States: Emerging evidence for both substitution and complementarity

BACKGROUND

The majority of adolescents and young adults (AYA) who use cannabis also use alcohol. Although cannabis use is increasing in the United States (US), it is not known whether the increase contributes to either increased co-use of alcohol and cannabis (e.g., complementarity) or replacement of alcohol with cannabis (e.g., substitution). The current study estimated the prevalence of alcohol use by cannabis use status among US AYA ages 12 to 25 in 2018 and trends in alcohol use by cannabis use status from 2002 to 2018.

METHODS

Data were drawn from the 2002 to 2018 National Survey on Drug Use and Health public use data files. The analytic sample included AYA ages 12 to 25 (2018 sample, n = 26,924; total combined sample 2002 to 2018, n = 576,053). Linear and logistic regression models were used to estimate past-month alcohol use, daily alcohol use, and average quantity of alcohol consumed among AYA with and without past-month cannabis use from 2002 to 2018.

RESULTS

In 2018, any alcohol use and daily alcohol use were significantly more common among AYA who used cannabis use than those who did not use cannabis. Overall, any alcohol use, daily alcohol use, and average drinks per day declined from 2002 to 2018 among AYA irrespective of recent cannabis use. However, the decline in any alcohol use, daily alcohol use, and average alcohol drinks per day was more rapid among AYA who used cannabis (daily and nondaily) than those who did not use cannabis. The rate of decline in average alcohol drinks per day was also higher among AYA with daily compared to nondaily cannabis use.

CONCLUSIONS

Even with declines in alcohol use over time, drinking is much more common among AYA who report cannabis than those without recent cannabis use, which is consistent with complementarity. Yet, because the decline in alcohol use has been more rapid among AYA who use cannabis, there is also evidence of substitution. Thus, the current data on alcohol and cannabis use are consistent with both complementarity and substitution. However, these relationships may change as cannabis legalization expands over time.