Cannabis-related medical diagnoses in Germany tripled from 1.1 to 3.7 per 1,000 between 2009 and 2021, outpacing the roughly doubling of use prevalence over the same period.
People following German cannabis policy, public health researchers, and anyone interested in how cannabis health impacts compare to use prevalence trends.
Cannabis diagnoses tripled while use roughly doubled
What the researchers found
Age-standardized cannabis use prevalence nearly doubled (5.7% to 10.6%), cannabis-related diagnoses more than tripled (1.1 to 3.7 per 1,000), and minor possession offences increased (1.8 to 3.1 per 1,000) between 2009 and 2021. The steepest increases in use and offences were among 40-59 year olds, while the largest diagnostic increases were in 35-44 year olds. Rates for minors remained relatively stable.
Why it matters
Germany was preparing to decriminalize cannabis when this study was conducted, making the baseline data on use, health problems, and legal consequences critical for evaluating the impact of policy changes. The finding that health problems rose faster than use itself suggests that either cannabis potency or patterns of problematic use are intensifying.
The numbers in context
Use prevalence: 5.7% to 10.6%. Diagnoses: 1.1 to 3.7 per 1,000. Offences: 1.8 to 3.1 per 1,000. Largest use/offence increases: ages 40-59. Largest diagnostic increases: ages 35-44. Cannabis-related problems more pronounced in Northern and city states.
How the study worked
Researchers analyzed three national routine data sources: population-based surveys for cannabis use prevalence, ICD-10 F12 code outpatient medical data for cannabis-related diagnoses, and registered narcotics law violations for minor possession offences. Age-standardized rates were calculated across German federal states from 2009 to 2021.
What this study cannot tell us
Outpatient diagnostic data depends on clinical coding practices, which may have changed over time (increased awareness could inflate apparent increases). Survey-based prevalence may undercount true use. The study period ends before legalization, so it captures pre-reform trends only.
How to read the evidence
Three national routine data sources covering all German federal states over 13 years. Strong population-level evidence, though changes in diagnostic practices may partly explain the diagnostic increase.
When this study was published
Published in 2025 with data through 2021.
The bigger picture
Germany legalized recreational cannabis in 2024, making this pre-legalization data invaluable as a baseline. The pattern of health problems rising faster than use is consistent with trends seen in other countries and may reflect higher-potency products or shifts in consumption patterns.
Questions still open
- Will legalization accelerate or slow the trend of increasing cannabis-related diagnoses? Why are middle-aged adults showing the steepest increases in use and offences?
Common questions
Why might health problems rise faster than use?
Did Germany legalize cannabis?
Read the original research
Cannabis use, health problems, and criminal offences in Germany: national and state-level trends between 2009 and 2021.
European archives of psychiatry and clinical neuroscience, 275(2), 555-564
Citation
Manthey, Jakob; Klinger, Sinja; Rosenkranz, Moritz; Schwarzkopf, Larissa. (2025). Cannabis use, health problems, and criminal offences in Germany: national and state-level trends between 2009 and 2021.. European archives of psychiatry and clinical neuroscience, 275(2), 555-564. https://doi.org/10.1007/s00406-024-01778-z