What the Ekocan Study on Hospital Admissions Examined
The investigation is part of the Ekocan research project, commissioned by the German Federal Ministry of Health in 2024. It is headed by Jakob Manthey at the University Medical Center Hamburg-Eppendorf. For the analysis, researchers used billing data from statutory health insurance funds covering the period from January 2022 to September 2025.
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Only inpatient stays in which a cannabis-related diagnosis was assigned as the primary diagnosis were included. These include ICD-10 codes F12.0 through F12.9 as well as T40.7. In total, 77,232 hospital admissions were analyzed. Researchers compared the twelve months before and after the Cannabis Act took effect.
Significant Rise in Intoxications and Psychosis Cases
Among adults, the total number of cannabis-related admissions rose by 5.6 percent. This corresponds to approximately 1,359 additional hospital cases in the year following the legislative change. The weekly rate per 1,000 hospital admissions climbed from 1.12 to 1.27.
Two diagnostic groups stood out particularly. Acute intoxications increased by 37.1 percent, and cannabis-induced psychosis cases rose by 16.4 percent. These two categories are driving the overall increase. For those seeking context on psychotic reactions, our overview of cannabis and psychosis identifies the key risk groups. A Vanderbilt study on concurrent use recently showed that combining cannabis with tobacco further increases the risk of psychosis in predisposed individuals.
Only Temporary Effect in Adolescents
The picture for adolescents is different. Shortly after partial legalization, the number of admissions initially rose by 14.9 percent. However, this effect weakened by 0.4 percentage points week after week and had disappeared after approximately 35 weeks. Over twelve months, roughly 91 additional cases accumulated. The weekly rate rose from 1.07 to 1.22 per 1,000 admissions.
This finding aligns with other studies that have found no sustained increase in consumption among minors. The temporary spike suggests a short-term curiosity effect rather than a lasting behavioral change. For prevention purposes, this age group remains a focus.
How Researchers Interpret the Data
The study authors urge caution in interpreting results. Billing data alone cannot definitively establish that the legislative change is the sole cause. Cannabis consumption in the general population has risen only moderately since April 2024. The study text states that findings point to a moderate immediate effect of the legislative change on the number of cannabis-specific hospital admissions in adults.
Researchers cite possible contributing factors including broader availability of high-potency medical cannabis and public debate that may have prompted some people to experiment. In parallel, the government is expanding accompanying research. Recently, the BLE approved the first four cannabis research projects. We also examined how legalization affects the black market in our CanG interim report.
Healthcare systems face a dual challenge. On one hand lies medical benefit—for example, in treating chronic pain or PTSD. On the other, education about dosing and risks is essential to prevent further increases in acute incidents. Reliable conclusions about long-term trends will only be possible with several years of data.
Frequently Asked Questions
By how much have cannabis-related hospital admissions increased?
Among adults, the total number of cannabis-related hospital admissions rose by 5.6 percent in the year following partial legalization. This represents approximately 1,359 additional cases. Most notably, acute intoxications increased by 37.1 percent and cannabis-induced psychosis by 16.4 percent.
Does the increase mean legalization is to blame?
Not necessarily. The study shows a temporal connection but cannot prove causation. Authors point out that overall consumption has risen only moderately and multiple factors could be at play, including greater availability of high-potency medical cannabis.
Are adolescents more severely affected?
No. While adolescents initially saw an increase of 14.9 percent, this effect disappeared after approximately 35 weeks. Over the entire year, only about 91 additional admissions accumulated. The effect was therefore only temporary.
What are cannabis-induced psychoses?
These are psychotic states that occur in close temporal connection with use. Typical symptoms include perceptual disturbances, delusions, or severe agitation. People with genetic predisposition and those using high-potency products are at particular risk.
Who conducted the study?
The Center for Interdisciplinary Addiction Research at the University Medical Center Hamburg-Eppendorf is responsible, as part of the Ekocan project. This project monitors the effects of the Cannabis Act on behalf of the Federal Ministry of Health. Results were published in Deutsches Ärzteblatt.
Überrascht dich der Anstieg cannabisbezogener Klinikeinweisungen seit April 2024?
Sources: Deutsches Ärzteblatt (ZIS/Ekocan Study, Manthey et al.), Center for Interdisciplinary Addiction Research at UKE.
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