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Citation
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L'Heureux S, Huot-Lavoie M, Bergeron A, Bergeron C, Blouin BP, Roy MA. Can. J. Psychiatry 2024; ePub(ePub): ePub. |
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Abstract
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Canadian government legalized cannabis on October 17, 2018, and the Province of Quebec established the government-owned Société Québécoise Du Cannabis (SQDC) as the sole authorized distributor. Studies investigating the relationship between cannabis legalization and psychosis are limited and have yielded mostly inconclusive results.1,2 A nationwide study in the United States observed no significant increase in psychosis diagnoses in states where cannabis was legalized.3 A study in Alberta and Ontario observed such an increase but interrupted time series analyses suggested that this was not due to cannabis legalization as it was the continuation of a trend antedating legalization.4 In Quebec, an observational study at Sherbrooke revealed a significant increase in cannabis use following legalization but no significant difference in consultations for psychosis.5
The present retrospective observational study examined the impact of cannabis legalization on the incidence of consultations for cannabis-related psychotic episodes in the adult population, by comparing the proportion of emergency department (ED) consultations for psychoses in which evidence for cannabis consumption was obtained before and after legalization. Comparatively to the Sherbrooke study, it assessed a longer observation period and focused on the adult population, considering the legal age of 18 years old for purchasing cannabis until January 1, 2020. This study included patients seeking psychiatric consultation for psychosis at one of the three psychiatric EDs in Quebec City, within the 12 months preceding legalization of cannabis (October 17, 2017-October 16, 2018) and the 12 months following legalization (October 17, 2018-October 16, 2019). Medical records of adults with an active episode of psychosis notwithstanding the diagnosis (substance-induced psychosis, schizophrenia spectrum disorder, depressive and bipolar disorders) were reviewed by three psychiatry residents. Individuals >65 years old and cases of only substance intoxication were excluded. The occurrence of >1 consultation within the same month was considered as a single episode as recommended in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Evidence of cannabis consumption came from an exhaustive review of medical records, including drug urine screening and clinical notes. Ethical approval was provided by the Research Ethics Committee of the CIUSSS-Capitale-Nationale. One-tailed chi-square test with a P ≤ 0.05 threshold for statistical significance was used to compare the proportion of ED consultations for psychoses with evidence of cannabis consumption before and after legalization. ...
Language: en |