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

Abstract

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.

Cannabis and Mental Health: Adverse Outcomes and Self-Reported Impact of Cannabis Use by Mental Health Status

“…The negative effects could be attributed to the fact that although cannabis may be initially used for immediate relief of symptoms, its effects are only short-term. Over time, consumers might be left with an increased inability to regulate symptoms of distress, leading to an increased vulnerability to negative mental health related outcomes (Koob & Le Moal, 2001;Lowe et al, 2019;McGuckin et al, 2020).…”

“…Additionally, the proportions of patients with mental health conditions reporting cannabis use prior to admission to inpatient psychiatry in Ontario has increased between 2007 and 2017, with the greatest increases among those with psychotic disorders and non-cannabis substance use disorder (McGuckin et al, 2020).…”