Psychosis hospitalizations among youth aged 10-29 in Denver increased significantly after both expanded medical cannabis access and recreational legalization, with CUD-involved cases quadrupling.
Child psychiatrists, public health officials, and policymakers evaluating cannabis legalization impacts.
CUD-involved psychosis hospitalizations in youth quadrupled from 2.0 to 8.5 per 100,000 after legalization
What the researchers found
Monthly psychosis hospitalization rates for youth rose from 21.9 per 100,000 pre-medical expansion to 28.0 post-expansion and 32.3 post-recreational legalization. Psychosis hospitalizations involving CUD increased most dramatically, from 2.0 to 3.4 to 8.5 per 100,000. Interrupted time series showed a significant trend change for CUD-involved psychosis following recreational legalization.
Why it matters
This is one of the first studies to link cannabis legalization milestones specifically to youth psychosis hospitalizations, with the CUD-involved cases providing the most compelling signal.
The numbers in context
Psychosis hospitalizations per 100,000: pre-Ogden 21.9, post-Ogden 28.0, post-legalization 32.3 (all differences p<0.05). CUD-involved: 2.0, 3.4, 8.5. Post-legalization CUD-psychosis trend: +0.11 per 100,000/month vs +0.02 pre-legalization. 68% male, 53% white, 59% Medicaid.
How the study worked
Interrupted time series analysis of Denver Health data (2005-2020) examining psychosis-related ED and hospital visits among youth aged 10-29 before and after the Ogden Memo (2009) and Amendment 64 (2012).
What this study cannot tell us
Single health system (Denver Health) may not represent all Colorado youth. Cannot establish individual-level causation. Increasing clinician awareness of CHS and cannabis-related conditions over time may inflate later rates. Other factors besides legalization changed during the study period.
How to read the evidence
Interrupted time series with clear policy anchors provides moderate causal evidence, limited by single health system and inability to control for all temporal confounders.
When this study was published
2025 publication with 2005-2020 Denver Health data.
The bigger picture
Colorado was one of the first states to legalize recreational cannabis and now has over a decade of post-legalization data. The quadrupling of CUD-involved psychosis hospitalizations is one of the strongest signals linking legalization to a specific psychiatric outcome in young people.
Questions still open
- Are the rising psychosis rates driven by increased potency, increased use, or increased clinical detection?
- How do Colorado youth psychosis rates compare to states without cannabis legalization?
Read the original research
Changes in psychosis-related emergency department and hospitalization rates among youth following cannabis legalization in Colorado.
Drug and alcohol dependence, 273, 112719
Citation
Joshi, Spruha; Snyder, Kyle M; Thurstone, Christian; Rivera, Bianca D; Feldman, Justin; Cerdá, Magdalena; Krawczyk, Noa. (2025). Changes in psychosis-related emergency department and hospitalization rates among youth following cannabis legalization in Colorado.. Drug and alcohol dependence, 273, 112719. https://doi.org/10.1016/j.drugalcdep.2025.112719
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