Few high school cannabis users quit on their own, but those who did showed improved attendance and homework completion

Only 14.8% of high school cannabis users reduced their use between grade levels, but students who quit showed significantly better class attendance and homework completion than those who continued using.

Zuckermann, Alexandra M et al.·Health promotion and chronic disease prevention in Canada : research·2020·Moderate EvidenceLongitudinal Cohort
RTHC-02938Longitudinal CohortModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Longitudinal Cohort
Evidence
Moderate Evidence
Sample
N=91,774

What This Study Found

Only 14.8% decreased use between grades, with two-thirds making only incremental changes. Cessation rates from daily and weekly use decreased each year. Students who quit had better odds of class attendance (OR=2.48) and homework completion (OR=2.32) compared to continuing users, but still had worse math performance than never-users (OR=0.55).

Key Numbers

91,774 observations. 14.8% reduced use between grades. Quitters vs. continuing users: attendance OR=2.48, homework OR=2.32. Quitters vs. never-users: math OR=0.55 for some subcategories. Cessation rates from daily/weekly use declined each year.

How They Did This

Longitudinal analysis of 91,774 linked observations from the COMPASS prospective cohort study of Canadian high school students (Grades 9-12, 2013-2017). Cannabis use change patterns tracked across grade transitions. Academic outcomes (math, English marks, homework, truancy) compared between quitters, continuing users, and never-users.

Why This Research Matters

This large longitudinal study shows that spontaneous cannabis cessation is uncommon among high school students, suggesting most teen users need external support. The academic improvements seen after quitting provide concrete motivation for cessation.

The Bigger Picture

The finding that cessation rates decrease each year suggests a narrowing window for intervention. School-based programs that support cannabis reduction early in high school may have the best chance of success.

What This Study Doesn't Tell Us

Observational data cannot prove that quitting caused academic improvements. Self-reported cannabis use and academic outcomes. Students who quit may differ systematically from those who continue. Canadian sample may not generalize to other countries.

Questions This Raises

  • ?Would targeted school-based cessation support increase quit rates?
  • ?Do academic improvements from quitting persist long-term?
  • ?What distinguishes the minority who spontaneously quit from those who continue?

Trust & Context

Key Stat:
Only 14.8% of teen cannabis users reduced use between grades
Evidence Grade:
Large prospective cohort with longitudinal tracking, but observational design and self-reported data.
Study Age:
2020 study using pre-legalization Canadian data (2013-2017). Provides baseline for evaluating post-legalization cessation patterns.
Original Title:
Cannabis cessation among youth: rates, patterns and academic outcomes in a large prospective cohort of Canadian high school students.
Published In:
Health promotion and chronic disease prevention in Canada : research, policy and practice, 40(4), 95-103 (2020)
Database ID:
RTHC-02938

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Follows a group of people over time to track how outcomes develop.

What do these levels mean? →

Frequently Asked Questions

Did quitting cannabis improve grades?

Quitters showed significantly better attendance and homework completion than continuing users. Some math performance improved, but quitters still scored below never-users, suggesting academic recovery may be partial.

Why did so few teens quit on their own?

Only 14.8% reduced use, and cessation rates from daily/weekly use dropped each year, suggesting cannabis use becomes harder to stop without external support as it continues through high school.

Read More on RethinkTHC

Cite This Study

RTHC-02938·https://rethinkthc.com/research/RTHC-02938

APA

Zuckermann, Alexandra M; Gohari, Mahmood R; de Groh, Margaret; Jiang, Ying; Leatherdale, Scott T. (2020). Cannabis cessation among youth: rates, patterns and academic outcomes in a large prospective cohort of Canadian high school students.. Health promotion and chronic disease prevention in Canada : research, policy and practice, 40(4), 95-103. https://doi.org/10.24095/hpcdp.40.4.01

MLA

Zuckermann, Alexandra M, et al. "Cannabis cessation among youth: rates, patterns and academic outcomes in a large prospective cohort of Canadian high school students.." Health promotion and chronic disease prevention in Canada : research, 2020. https://doi.org/10.24095/hpcdp.40.4.01

RethinkTHC

RethinkTHC Research Database. "Cannabis cessation among youth: rates, patterns and academic..." RTHC-02938. Retrieved from https://rethinkthc.com/research/zuckermann-2020-cannabis-cessation-among-youth

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.