Here’s a recent study examining rates of emergency department encounters and hospitalizations in Colorado among youth following cannabis legalization.
Overall, I find several portions of this work rather interesting.
Below, I provide some quotations from the Abstract, Discussion, and Conclusion sections.
The information below brings to mind for me the positive movement forward that has been achieved over decades in the USA related to cigarette smoking.
That is to say, it seems to me we have not applied the lessons learned from our decades-long society-wide project with tobacco and cigarettes to our (proactive) management of cannabinoids in the USA.
Abstract:
An increasing number of U.S. states have legalized cannabis, but the effect on adolescent and young adult psychosis-related hospitalizations remains under-studied.
Using data from Denver Health between 2005 and 2020, we examined associations between implementation of the Ogden Memo (expanding use of medical cannabis in Colorado, October 2009) and Amendment 64 (legalizing adult-use cannabis in Colorado, November 2012) and trends in psychosis-related emergency department and hospital visits with and without cannabis use disorder (CUD) among youth aged 10–29.
Patients with psychosis hospitalizations were predominately male (68 %), white (53 %), and Medicaid recipients (59 %).
Significant increases…were observed in the monthly average rate of psychosis hospitalizations between pre-Ogden memo (21.9 per 100,000) and post-Ogden memo pre-legalization (28.0 per 100,000) and post-legalization (32.3 per 100,000).
Similarly, significant increases…were observed in the monthly average rate of psychosis hospitalizations involving CUD between pre-Ogden memo (2.0 per 100,000), post-Ogden memo and pre-legalization (3.4 per 100,000), and post-legalization (8.5 per 100,000).
Interrupted time series modeling found a significant difference in the trends for psychosis hospitalizations involving CUD following recreational legalization…
Discussion:
…public health responses should aim to mitigate risky use via both regulation of sales and the content of products on the supply side, and via demand-side interventions to reduce risky use.
The greatest links to increased psychosis incidence among people who use cannabis have also been found in those who start using earlier, use more frequently, and in high potencies…
Thus, harm reduction efforts to delay onset of use and reduce the frequency of use may be particularly important. Many experts, for example, have called for placing limits on marketing of cannabis products to youth, such as candy wrapper branding and flavored products that are known to enhance use of cannabis in early age groups…
…the large rise in visits for psychosis involving cannabis is likely not only related to cannabis-induced psychosis alone but also to potentially greater access or use of cannabis among individuals with psychotic or other mental health disorders.
Many studies point to high levels of cannabis use as a form of self-medication among individuals with mental illness, which can also lead to allostasis, whereby individuals who find relief of symptoms during intoxication tend to increase use, leading to exacerbation of affective symptoms during withdrawal and in turn increased cannabis use…
More research is needed to understand whether and by what mechanisms cannabis may be contributing to exacerbation or reported relief of psychosis symptoms…and to inform best practices for patients with comorbid psychosis and cannabis use to identify effective therapeutic interventions and strategies. This is particularly important early on in psychosis to prevent chronic psychosis disorders and worsening symptoms…
Conclusion:
The findings of this study suggest a modest increase in overall emergency department and hospitalization visits with any psychosis diagnosis among youth after legalization of recreational cannabis. These increases were primarily among young adults aged 21–29, rather than younger age groups. We also found a significant rise in psychosis hospitalizations that specifically contain a CUD diagnosis following legalization across all age groups. Given the adoption of increasingly permissive cannabis laws, there is a need to plan effective public health responses that could mitigate unintended consequences related to cannabis use.
Reference
Joshi, Snyder, Thurstone, Rivera, Feldman, Cerdá & Krawczyk. Changes in psychosis-related emergency department and hospitalization rates among youth following cannabis legalization in Colorado. Drug and Alcohol Dependence. 273, 2025, 112719. doi.org/10.1016/j.drugalcdep.2025.112719.
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