Longitudinal changes in cannabis use and misuse in the 5 years following recreational cannabis legalization in Canada: A prospective cohort study of community adults
Notice bibliographique
Résumé
Abstract Importance A growing number of jurisdictions have legalized recreational cannabis for adults, but most evaluations have used repeated cross-sectional designs, preventing examination of within-person and subgroup trajectories across legalization. Objective To examine changes in cannabis use and misuse in the five years following legalization in Canada – the first G7 country to legalize adult recreational cannabis use – both overall and by pre-legalization cannabis use frequency using a longitudinal design. Design Prospective cohort study with 11 biannual assessments from September 2018 to October 2023. Mean retention was 90% across all waves. Setting Ontario, Canada. Participants Sample of 1,428 (60.2% female, M age =34.5) community adults aged 18 to 65 years. Exposure Five years of recreational cannabis legalization (the baseline wave was immediately prior to legalization). Main outcome and measures Primary outcomes were cannabis use frequency and cannabis misuse (CUDIT-R score). Pre-legalization cannabis use frequency, age, and sex were examined as moderators. Secondary outcomes included changes in cannabis product preferences over time. Results Linear mixed effects modelling found a significant increase in cannabis use frequency, such that the mean proportion of days using cannabis increased by 0.35% ( p <.001) per year in the overall sample (1.75% over 5 years). In contrast, CUDIT-R scores (on scale of 0 to 32) decreased significantly overall (b=-0.08 [-0.4 over 5 years], p <.001), most notably following the onset of the COVID-19 pandemic. Interaction analyses indicated that pre-legalization cannabis use frequency significantly moderated changes for both outcomes ( p <.001). Specifically, cannabis use and misuse decreased among pre-legalization frequent consumers and modestly increased among occasional/non-users. Cannabis product preferences shifted away from dried flower, hashish, concentrates, oil, tinctures, and topicals to edibles, liquids, and vape pens. Conclusions and Relevance In the five years following legalization, cannabis use frequency increased modestly, while cannabis misuse decreased modestly in a longitudinal observational cohort of Canadian adults. These changes were substantially moderated by pre-legalization cannabis use, with more frequent consumers of cannabis pre-legalization exhibiting the largest decreases in both outcomes. Although longer-term surveillance is required, these results suggest Canadian recreational cannabis legalization was associated with modest negative consequences and some evidence of positive outcomes among nonclinical community adults. Key points Question Did cannabis use or misuse change among adults in the five years following recreational cannabis legalization in Canada (overall and by pre-legalization cannabis use frequency)? Findings Overall, cannabis use frequency increased significantly while misuse decreased significantly, with small effect sizes for both. Pre-legalization cannabis use significantly moderated these changes. Product preferences shifted from dried flower, hashish, and concentrates to edibles, liquids, and vape pens. Meaning From a public health standpoint, these findings suggest both a modest negative consequence (small increase in cannabis use frequency) and positive outcomes (small decrease in cannabis misuse, and transition from combustible to non-combustible products).
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Comment cette classification a été obtenuedéplier
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Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,001 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,001 | 0,003 |
| Études des sciences et des technologies | 0,003 | 0,001 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».