Age-period-cohort analysis of past 12-month cannabis use in Germany (1995-2021)

In 2024, cannabis was partially legalized for recreational purposes in Germany. With a growing prevalence of persons who used cannabis in the past 12 months, and the health risks associated with cannabis use, it is imperative to examine usage behavior patterns in greater detail. The present analysis measured the impact of age, time period and birth cohort on the prevalence of cannabis consumption in the past 12 months in Germany.

Longitudinal study using data from 10 waves (1995-2021) of the German Epidemiological Survey of Substance Abuse (ESA), a cross-sectional nationally representative household survey of individuals between the ages of 18 and 59 or 64 years.

Germany.

N_total = 78 678 German-speaking adults between the ages of 18 and 59 years.

Self-report of cannabis use in the last 12 months as well as alcohol use and smoking conventional tobacco products in the last 30 days.

We employed binary logistic regression using a generalized additive model to examine age, period and cohort effects, as well as covariate effects on past 12-month cannabis use. Over time, both period and cohort had an increasing effect, while an increase in age corresponded to a decrease in prevalence. Specifically, the odds ratio (OR) for cannabis use decreased from 9.44 [95% confidence interval (CI) = 8.17-10.9] at age 18 years to 0.13 (95 CI = 0.10-0.17) at age 59 years. Period effects also showed an increase, with the OR rising from 0.33 (95% CI = 0.26-0.43) in 1995 to 2.96 (95% CI = 2.55-3.43) in 2021, while cohort effects increased from 0.02 (95% CI = 0.001-0.05) for those born in 1936 to 16.69 (95% CI = 13.8-20.8) for those born in 2002. Additionally, persons using cannabis had a higher likelihood of also drinking alcohol and smoking conventional tobacco products in the last 30 days.

In Germany, the odds of being a past-12-month cannabis consumer appears to decline with increasing age, indicating that only a small proportion of consumers engage in cannabis use throughout their whole lives, with a peak prevalence occurring at a younger age.