Cannabinoid-related psychiatric hospitalizations increased nearly 5-fold in Germany over 18 years

What the researchers found

All categories of cannabinoid-related psychiatric hospitalizations increased significantly: intoxications, harmful use, dependence syndrome, withdrawal, psychotic disorders, and residual/late-onset psychotic disorders. The overall relative frequency increased 4.8-fold comparing 2000 and 2018. Meanwhile, alcohol dependence admissions remained stable and schizophrenia-spectrum admissions slightly decreased.

Why it matters

The dramatic increase in cannabinoid-related psychiatric hospitalizations coincides with rising recreational use, synthetic cannabinoid availability, and increasing THC content in cannabis preparations.

The numbers in context

4.8-fold increase in relative frequency from 2000 to 2018. All six subcategories showed statistically significant increases (p<0.001 for most). Schizophrenia admissions slightly decreased (p=0.008). Alcohol dependence unchanged (p=0.844).

How the study worked

Analysis of all inpatient hospital diagnoses in Germany from 2000-2018 using Federal Statistical Office (Destatis) data. Linear trend analysis of absolute and relative annual frequencies of ICD-10 cannabinoid-related diagnoses versus control diagnoses.

What this study cannot tell us

Administrative data may reflect changes in diagnostic practices, awareness, or healthcare-seeking behavior rather than true incidence changes. Cannot link to individual-level cannabis use data.

How to read the evidence

Complete national hospital data providing a reliable trend, though administrative data cannot determine causation.

When this study was published

Published in 2022 with German hospital data from 2000-2018.

The bigger picture

The divergence between increasing cannabinoid-related admissions and stable/decreasing alcohol and schizophrenia admissions suggests a specific cannabis-related public health trend rather than a general increase in psychiatric hospitalizations.

Questions still open

• How much of the increase is driven by synthetic cannabinoids versus natural cannabis? Are rising THC concentrations a major contributing factor?

Common questions

Read the original research

Incidence of inpatient cases with mental disorders due to use of cannabinoids in Germany: a nationwide evaluation.

European journal of public health, 32(2), 239-245

Citation

Gahr, Maximilian; Ziller, Julia; Keller, Ferdinand; Muche, Rainer; Preuss, Ulrich W; Schönfeldt-Lecuona, Carlos. (2022). Incidence of inpatient cases with mental disorders due to use of cannabinoids in Germany: a nationwide evaluation.. European journal of public health, 32(2), 239-245. https://doi.org/10.1093/eurpub/ckab207

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