States with More Liberal Cannabis Laws Had More Psychosis Hospitalizations

What the researchers found

There were an estimated 129,070 hospital discharges for psychosis associated with cannabis in 2017. The Pacific division had 55% higher odds of such discharges (aOR=1.55, 95% CI 1.25-1.93). A cannabis legality score correlated significantly with the proportion of psychosis-cannabis hospitalizations (r=0.67, P<0.05).

Why it matters

This national-level data provides evidence that more liberal cannabis legalization is associated with more psychosis-related hospitalizations, a finding with direct policy implications.

The numbers in context

129,070 psychosis-cannabis hospital discharges; Pacific division aOR 1.55; legality-psychosis correlation r=0.67 (P<0.05)

How the study worked

Analysis of the 2017 National Inpatient Sample database using multivariable logistic regression comparing psychosis-cannabis hospitalizations across U.S. census divisions. Cannabis legality scores were population-weighted sums of state-level legal status.

What this study cannot tell us

Cross-sectional data from one year. Cannot establish causation. Higher rates in legal states could reflect better detection, more use, higher potency, or other factors. Hospital discharge codes may not accurately capture cannabis involvement.

How to read the evidence

National database analysis with multivariate adjustment, but cross-sectional design and potential coding variability limit causal inference.

When this study was published

Published in 2022

The bigger picture

As more states legalize cannabis, monitoring psychiatric hospitalizations related to cannabis use becomes increasingly important. This geographic variation suggests legalization may have measurable public health impacts on psychosis.

Questions still open

• Are the higher rates in legal states driven by increased cannabis use, higher potency products, or more clinicians coding cannabis involvement? Would longitudinal data show psychosis hospitalizations increasing after legalization?

Common questions

Read the original research

Geographical variation in hospitalization for psychosis associated with cannabis use and cannabis legalization in the United States: Submit to: Psychiatry Research.

Psychiatry research, 308, 114387

Citation

Moran, Lauren V; Tsang, Erica S; Ongur, Dost; Hsu, John; Choi, May Y. (2022). Geographical variation in hospitalization for psychosis associated with cannabis use and cannabis legalization in the United States: Submit to: Psychiatry Research.. Psychiatry research, 308, 114387. https://doi.org/10.1016/j.psychres.2022.114387

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