Changes in psychosis-related emergency department and hospitalization rates among youth following cannabis legalization in Colorado
Spruha Joshi, Kyle M. Snyder, Christian Thurstone, Bianca D. Rivera, J. Feldman, Magdalena Cerdá, Noa Krawczyk
Drug and Alcohol Dependence May 1, 2025 DOI: 10.1016/j.drugalcdep.2025.112719 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study using interrupted time series analysis Peer reviewed |
|---|---|
| Population | Youth aged 10-29 with psychosis-related emergency department and hospital visits at Denver Health, 2005-2020; predominantly male (68%), white (53%), and Medicaid recipients (59%) |
| Duration | 2005-2020 |
| Topics | Cannabis |
| Key findings | Monthly average psychosis hospitalization rates among youth rose from 21.9 per 100,000 before Colorado's Ogden Memo to 28.0 after it and 32.3 after recreational legalization, while psychosis hospitalizations involving cannabis use disorder rose from 2.0 to 3.4 to 8.5 per 100,000. Interrupted time series modeling showed a significant acceleration in the trend for cannabis-use-disorder psychosis hospitalizations after recreational legalization, with the change in average monthly rate increasing from 0.02 to 0.11 per 100,000. The authors suggest these findings indicate a need for public health planning. |
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 2005–2020, 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 (p<0.05) were observed in the monthly average rate of psychosis hospitalizations pre-Ogden memo (21.9 per 100,000), post-Ogden memo and pre-legalization (28.0 per 100,000) and post-legalization (32.3 per 100,000). Similarly, significant increases (p<0.05) were observed in the monthly average rate of psychosis hospitalizations involving CUD 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 (change in average monthly rate went from 0.02/100,000 (95% CI −0.02, 0.06) to 0.11/100,000 (95% CI 0.09, 0.13), (difference (0.09 (95%CI 0.05, 0.14)). Findings suggest an increase in overall hospital encounters for psychosis among youth after the legalization of recreational cannabis. 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.