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. 2021 Dec;66(12):1059-1068.
doi: 10.1177/0706743720984679. Epub 2020 Dec 31.

How High? Trends in Cannabis Use Prior to First Admission to Inpatient Psychiatry in Ontario, Canada, between 2007 and 2017

Taylor McGuckin  1 , Mark A Ferro  1 , David Hammond  1 , Shannon Stewart  2 , Bridget Maloney-Hall  3 , Nawaf Madi  4 , Amy Porath  3 , Christopher M Perlman  1
Affiliations

How High? Trends in Cannabis Use Prior to First Admission to Inpatient Psychiatry in Ontario, Canada, between 2007 and 2017

Taylor McGuckin et al. Can J Psychiatry. 2021 Dec.

Abstract
in English, French

Objectives: To examine the trends in cannabis use within 30 days of first admission to inpatient psychiatry in Ontario, Canada, between 2007 and 2017, and the characteristics of persons reporting cannabis use.

Methods: A retrospective cross-sectional analysis was conducted for first-time admissions to nonforensic inpatient psychiatric beds in Ontario, Canada, between January 1, 2007, and December 31, 2017, using data from the Ontario Mental Health Reporting System (N = 81,809).

Results: Across all years, 20.1% of patients reported cannabis use within 30 days of first admission. Use increased from 16.7% in 2007 to 25.9% in 2017, and the proportion with cannabis use disorders increased from 3.8% to 6.0%. In 2017, 47.9% of patients aged 18 to 24 and 39.2% aged 25 to 34 used cannabis, representing absolute increases of 8.3% and 10.7%, respectively. Increases in cannabis use were found across almost all diagnostic groups, with the largest increases among patients with personality disorders (15% increase), schizophrenia or other psychotic disorders (14% increase), and substance use disorders (14% increase). A number of demographic and clinical factors were significantly associated with cannabis use, including interactions between schizophrenia and gender (area under the curve = 0.88).

Conclusions: As medical cannabis policies in Canada have evolved, cannabis use reported prior to first admission to inpatient psychiatry has increased. The findings of this study establish a baseline for evaluating the impact of changes in cannabis-related policies in Ontario on cannabis use prior to admission to inpatient psychiatry.

Objectifs:: Examiner les tendances de l’usage du cannabis dans les 30 jours de la première hospitalisation en psychiatrie en Ontario, Canada entre 2007 et 2017, et les caractéristiques des personnes déclarant utiliser du cannabis.

Méthodes:: Une analyse transversale rétrospective a été menée pour la première hospitalisation dans des lits de psychiatrie non légale en Ontario, Canada entre le 1er janvier 2007 et le 31 décembre 2017 à l’aide du Système d’information ontarien sur la santé mentale (N = 81 809).

Résultats:: Sur toutes ces années, 20,1 % des patients ont déclaré utiliser du cannabis dans les 30 jours de la première hospitalisation. L’usage a augmenté de 16,7 % en 2007 à 25,9 % en 2017, et la proportion de troubles d’utilisation du cannabis a augmenté de 3,8 % à 6,0 %. En 2017, 47,9 % des patients de18 à 24 ans et 39,2 % de ceux âgés de 25 à 34 ans utilisaient du cannabis, représentant des augmentations absolues de 8,3 % et 10,7 %, respectivement. Les augmentations de l’usage du cannabis se voyaient dans presque tous les groupes diagnostiques, et l’augmentation la plus forte se trouvait chez les patients souffrant de troubles de la personnalité. (15 % d’augmentation), de schizophrénie ou d’autres troubles psychotiques (14 % d’augmentation), et de troubles d’utilisation de substances (14 % d’augmentation). Un certain nombre de données démographiques et de facteurs cliniques étaient significativement associés à l’usage du cannabis, notamment les interactions entre la schizophrénie et le sexe (AUC = 0,88).

Conclusions:: Comme les politiques sur le cannabis médical ont évolué au Canada, l’usage du cannabis déclaré avant la première hospitalisation en psychiatrie a augmenté. Les résultats de cette étude établissent une base afin d’évaluer l’impact des changements de politiques liées au cannabis en Ontario sur l’usage du cannabis avant l’hospitalisation en psychiatrie.

Keywords: cannabis; cannabis use disorders; health policy; inpatient psychiatry; interRAI; mental health; self-medication; substance use.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Mark Ferro serves on the editorial board of the Canadian Journal of Psychiatry. The remaining authors have no conflicts of interest to declare.

Figures

Figure 1.
Figure 1.
Percentage of patients with and without psychotic disorders, by gender, who used cannabis within 30 days of first hospital visit to inpatient psychiatry.
See this image and copyright information in PMC

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