Cannabis use, health problems, and criminal offences in Germany: national and state-level trends between 2009 and 2021

The German federal government plans to decriminalise cannabis. The impact of this policy on use prevalence, cannabis-related health and legal problems cannot be fully anticipated and should be viewed in context with current trends. We used routine data on (a) cannabis use (population-based surveys), (b) cannabis-related diagnoses (ICD-10 code F12) in outpatient medical settings and (c) minor law offences (registered violations against the narcotics law for possessing small amounts) to analyse age and sex-specific trends by federal state between 2009 and 2021. To enable comparisons across time and federal state besides crude prevalence rates, age-standardised rates were calculated. Between 2009 and 2021, the age-standardised prevalence of cannabis use (5.7–10.6