Cannabis legalization leads to surprising shifts in youth usage patterns

NewsGuard 100/100 Score

A recent JAMA Network Open study discusses changes in the frequency of cannabis use and its consequences in a sample of high-risk young adults in Canada.

Study: Cannabis Use Frequency and Cannabis-Related Consequences in High-Risk Young Adults Across Cannabis Legalization. Image Credit: Canna Obscura /


The legalization of recreational cannabis use leads to an increase in the frequency of its use and several adverse consequences, especially among young adults between 18 and 29 years of age. These young adults are particularly vulnerable, as the consumption of cannabis and alcohol often co-occurs, which leads to further adverse consequences. Despite this, few studies have analyzed patterns of cannabis use in this population. 

Several American studies that analyzed the impacts of legalization on young adults presented mixed results. Although some studies documented that following legalization, the frequency of cannabis use increased, most studies have not reported a statistically significant increase.

Although young adults consume more cannabis than other age groups, there remains a lack of research on this population. This is particularly true for longitudinal studies investigating legalization's various impacts.

Longitudinal data aid in estimating rates of change in cannabis use, characterization of within-person changes, and identifying factors influencing cannabis use, such as income or sex.

About the study

The current study addresses these research gaps by longitudinally studying a cohort of young adults with a history of substance use pre-legalization. The primary aim was to explore the relationship between cannabis legalization, frequency of cannabis use, and adverse consequences. The secondary aim was to examine factors influencing cannabis use, such as sex, education, income, and the frequency of use pre-legalization.

The cohort comprised young adults in Ontario, Canada, between 19.5 and 23 years of age. About 65% of the study participants reported cannabis use in the previous month and regular heavy episodic drinking at enrollment.

Between February 2017 and February 2020, study participants were surveyed every four months. This provided researchers with three pre-legalization and four post-legalization waves.

Key findings

The study sample consisted of 619 participants, with the mean and standard deviation of age being 21 and 1.2 years, respectively. About 56% of participants were female, and 53% had a bachelor's degree at the most recent time point. Among 33% of participants, occasional cannabis use was the most common pre-legalization.

Overall, a decrease in cannabis use was observed, which is consistent with substance use patterns in this age group in the absence of any policy change. The observed changes were not significantly affected by cannabis legalization.

Most frequent cannabis users in the pre-legalization period were associated with a significant decline in its use post-legalization. Consequently, a marked reduction in cannabis-related adverse consequences was also reported.

Comparatively, non-users in the recent period of pre-legalization increased their use over time. However, this group was not associated with an increased risk of adverse consequences.

Importantly, complete non-users in the pre-legalization period were associated with no significant increases in consequences or use post-legalization. Since an increase in use was observed for a sub-group and no marked reduction was noted, the determinants of cannabis use in young adults must be further studied.

Strengths and limitations

The current study is the first longitudinal analysis of the impact of Canadian cannabis legalization on young adults that included multiple pre- and post-legalization time points. Due to these unique features, the study design is well-suited to be applied in other jurisdictions, as legalization policies could vary across regions.

The current study did not consider the general population and only included those who used cannabis pre-legalization. Arguably, these individuals are of most interest; however, the study findings do not apply to the general population, as legalization may have altered patterns of cannabis use and consequences in groups not included in this study sample. A fundamental limitation was the lack of a control group to study the effects of legalization in a natural experiment setting.


Frequent cannabis users in the pre-legalization period reduced use post-legalization and, as a result, were associated with fewer cannabis-related adverse consequences. This finding is consistent with the well-documented aging-out patterns of substance use.

Comparatively, individuals not using cannabis in the pre-legalization period reported a modest but significant increase in use over time. Given these patterns, more longitudinal studies are needed to analyze the effects of cannabis legalization further and devise evidence-based public policies.

Journal reference:
  • Doggett, A., Belisario, K., McDonald, A. J., et al. (2023) Cannabis Use Frequency and Cannabis-Related Consequences in High-Risk Young Adults Across Cannabis Legalization. JAMA Network Open 6(9). doi:10.1001/jamanetworkopen.2023.36035
Dr. Priyom Bose

Written by

Dr. Priyom Bose

Priyom holds a Ph.D. in Plant Biology and Biotechnology from the University of Madras, India. She is an active researcher and an experienced science writer. Priyom has also co-authored several original research articles that have been published in reputed peer-reviewed journals. She is also an avid reader and an amateur photographer.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Bose, Priyom. (2023, October 02). Cannabis legalization leads to surprising shifts in youth usage patterns. News-Medical. Retrieved on April 23, 2024 from

  • MLA

    Bose, Priyom. "Cannabis legalization leads to surprising shifts in youth usage patterns". News-Medical. 23 April 2024. <>.

  • Chicago

    Bose, Priyom. "Cannabis legalization leads to surprising shifts in youth usage patterns". News-Medical. (accessed April 23, 2024).

  • Harvard

    Bose, Priyom. 2023. Cannabis legalization leads to surprising shifts in youth usage patterns. News-Medical, viewed 23 April 2024,


  1. Brian Kelly Brian Kelly United States says:

    Legalize federally now. What's legal to possess and consume in nearly half of The United States should not make you a criminal in states still being governed by woefully ignorant prohibitionist politicians.

    Cannabis consumers in all states deserve and demand equal rights and protections under our laws that are currently afforded to the drinkers of far more dangerous and deadly, yet perfectly legal, widely accepted, endlessly advertised and even glorified as an All-American pastime, alcohol.

    Plain and simple!

    Legalize Nationwide Federally Now!

    Fear of Cannabis Legalization Nationwide is unfounded. Not based on any science or fact whatsoever. So please prohibitionists, we beg you to give your scare tactics, "Conspiracy Theories" and "Doomsday Scenarios" over the inevitable Legalization of Cannabis Nationwide a rest. Nobody is buying them anymore these days. Okay?

    Furthermore, if all prohibitionists get when they look into that nice, big and shiny crystal ball of theirs, while wondering about the future of cannabis legalization, is horror, doom, and despair, well then I suggest they return that thing as quickly as possible and reclaim the money they shelled out for it, since it's obviously defective.

    The prohibition of cannabis has not decreased the supply nor the demand for cannabis at all. Not one single iota, and it never will. Just a huge and complete waste of our tax dollars to continue criminalizing citizens for choosing a natural, non-toxic, relatively benign plant proven to be much safer than alcohol.

    If prohibitionists are going to take it upon themselves to worry about "saving us all" from ourselves, then they need to start with the drug that causes more death and destruction than every other drug in the world COMBINED, which is alcohol!

    Why do prohibitionists feel the continued need to vilify and demonize cannabis when they could more wisely focus their efforts on a real, proven killer, alcohol, which again causes more destruction, violence, and death than all other drugs, COMBINED?

    Prohibitionists really should get their priorities straight and/or practice a little live and let live. They'll live longer, happier, and healthier, with a lot less stress if they refrain from being bent on trying to control others through Draconian Cannabis Laws.

  2. Brian Kelly Brian Kelly United States says:

    What we certainly don't need are anymore people who feel justified in appointing themselves to be self-deputized morality police.

    We are very capable of choosing for ourselves if we want to consume cannabis, a far less dangerous choice over alcohol, and we definitely don't need anyone dictating how we should live our own lives.

    We can't just lock up everyone who does things prohibitionists don't personally approve of.

    "Cannabis is 114 times safer than drinking alcohol"

    "Cannabis may be even safer than previously thought, researchers say"

    "Cannabis may be even safer than previously thought, researchers say New study: We should stop fighting Cannabis legalization and focus on alcohol and tobacco instead By Christopher Ingraham February 23

    Compared with other recreational drugs — including alcohol — Cannabis may be even safer than previously thought. And researchers may be systematically underestimating risks associated with alcohol use.

    Those are the top-line findings of recent research published in the journal Scientific Reports, a subsidiary of Nature. Researchers sought to quantify the risk of death associated with the use of a variety of commonly used substances. They found that at the level of individual use, alcohol was the deadliest substance, followed by heroin and cocaine."
    -Washington Post

    "The report discovered that Cannabis is 114 times less deadly than alcohol. Researchers were able to determine this by comparing the lethal doses with the amount of typical use. Through this approach, Cannabis had the lowest mortality risk to users out of all the drugs they studied. In fact—because the numbers were crossed with typical daily use—Cannabis is the only drug that tested as "low risk."

  3. Brian Kelly Brian Kelly United States says:

    There is absolutely no doubt now that the majority of Americans want to completely legalize cannabis nationwide. Our numbers grow on a daily basis.

    The prohibitionist view on cannabis is the viewpoint of a minority and rapidly shrinking percentage of Americans. It is based upon decades of lies and propaganda.

    Each and every tired old lie they have propagated has been thoroughly proven false by both science and society.

    Their tired old rhetoric no longer holds any validity. The vast majority of Americans have seen through the sham of cannabis prohibition in this day and age. The number of prohibitionists left shrinks on a daily basis.

    With their credibility shattered, and their not so hidden agendas visible to a much wiser public, what's left for a cannabis prohibitionist to do?

    Maybe, just come to terms with the fact that Cannabis Legalization Nationwide is an inevitable reality that's approaching much sooner than prohibitionists think, and there is nothing they can do to stop it!

    Legalize Nationwide!...and Support All Cannabis Legalization Efforts!

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Nano-sized toxic metals found in cannabis vaping liquids even before the first use