Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
Department of Family Medicine, University of Ottawa, Ottawa, ON, Canada.
Mol Psychiatry. 2023 Oct;28(10):4251-4260. doi: 10.1038/s41380-023-02185-x. Epub 2023 Jul 27.
A major public health concern of cannabis legalization is that it may result in an increase in psychotic disorders. We examined changes in emergency department (ED) visits for cannabis-induced psychosis following the legalization and subsequent commercialization (removal of restrictions on retail stores and product types) of non-medical cannabis in Ontario, Canada (population of 14.3 million). We used health administrative data containing the cause of all ED visits to examine changes over three periods; 1) pre-legalization (January 2014-September 2018); 2) legalization with restrictions (October 2018 - February 2020); and 3) commercialization (March 2020 - September 2021). We considered subgroups stratified by age and sex and examined cocaine- and methamphetamine-induced psychosis ED visits as controls. During our study, there were 6300 ED visits for cannabis-induced psychosis. The restricted legalization period was not associated with changes in rates of ED visits for cannabis-induced psychosis relative to pre-legalization. The commercialization period was associated with an immediate increase in rates of ED visits for cannabis-induced psychosis (IRR 1.30, 95% CI 1.02-1.66) and no gradual monthly change; immediate increases were seen only for youth above (IRR 1.63, 1.27-2.08, ages 19-24) but not below (IRR 0.73 95%CI 0.42-1.28 ages, 15-18) the legal age of purchase, and similar for men and women. Commercialization was not associated with changes in rates of ED visits for cocaine- or methamphetamine-induced psychosis. This suggests that legalization with store and product restrictions does not increase ED visits for cannabis-induced psychosis. In contrast, cannabis commercialization may increase cannabis-induced psychosis presentations highlighting the importance of preventive measures in regions considering legalization.
大麻合法化的一个主要公共卫生问题是，它可能导致精神病的发病率增加。我们研究了在加拿大安大略省大麻非医用合法化和随后商业化（取消对零售店和产品类型的限制）后，急诊室（ED）因大麻引起的精神病就诊人数的变化。我们使用包含所有 ED 就诊原因的健康管理数据，检查了三个时期的变化：1）合法化前（2014 年 1 月至 2018 年 9 月）；2）有限制的合法化（2018 年 10 月至 2020 年 2 月）；3）商业化（2020 年 3 月至 2021 年 9 月）。我们按年龄和性别分层考虑了亚组，并将可卡因和甲基苯丙胺引起的精神病 ED 就诊作为对照。在我们的研究期间，有 6300 例因大麻引起的精神病的 ED 就诊。与合法化前相比，限制合法化期间 ED 因大麻引起的精神病就诊率没有变化。商业化期间与 ED 因大麻引起的精神病就诊率的立即增加有关（IRR 1.30，95%CI 1.02-1.66），没有逐月逐渐变化；仅在年龄在（IRR 1.63，1.27-2.08，19-24 岁）以上的年轻人中看到即时增加，但在（IRR 0.73，95%CI 0.42-1.28，15-18 岁）以下的年轻人中没有看到即时增加，而且男性和女性的情况相同。商业化与 ED 因可卡因或甲基苯丙胺引起的精神病就诊率的变化无关。这表明，有限制的商店和产品限制的合法化不会增加因大麻引起的精神病就诊。相反，大麻商业化可能会增加因大麻引起的精神病发作，这凸显了在考虑合法化的地区采取预防措施的重要性。
