Ecological momentary insights into cannabis use and its contexts: a pre-post legalization study in Germany.

Diallo L.; Spitta G.; Krasniqi S.; Bahr N.; Doerr S.; Reichert D.; Reichert M.; Wiedenhoeft J.; Priemer U.; Banaschewski T. et al. · Scientific reports · 2026

**Background & Methods** This ecological momentary assessment (EMA) study examined real-time cannabis consumption patterns in 49 German participants (34.7% female, mean age 33.8±11 years) during the immediate pre- and post-legalization period surrounding Germany's recreational cannabis decriminalization in April 2024. Daily consumption data were collected via EMA methodology to capture contextual factors and usage patterns before and after the legal reform. **Key Findings** • Following legalization, consumed amounts selectively increased among younger individuals (β=0.01, 95%CI=0.00-0.02, z=3.05, p<0.05), demonstrating age-dependent changes in consumption behavior post-reform. • Consumption context significantly shifted: amounts increased in outdoor settings (β=0.19, 95%CI=0.04-0.34, z=2.51, p<0.05) but decreased substantially in public settings (β=-0.46, 95%CI=-0.66 to -0.25, z=-4.36, p<0.05), suggesting legalization altered where individuals chose to use cannabis. • Holiday periods showed markedly elevated consumption likelihood (β=3.91, 95%CI=1.68-9.08, z=3.17, p<0.05), indicating temporal patterns in usage following legal changes. **Dosage & Administration** Not reported. The study focused on consumed amounts and contextual patterns rather than specific dosing parameters or routes of administration. **Safety & Adverse Effects** Not reported. While the abstract acknowledges that heavy cannabis use is linked to psychosis, anxiety, and depression globally, the study did not measure or report adverse effects in this particular cohort during the study period. **Evidence Quality** This study represents early post-legalization real-world evidence with notable limitations. The small sample size (n=49) and cross-sectional pre-post design without control group limit generalizability and causal inference. EMA methodology provides ecological validity through real-time data capture, reducing recall bias compared to retrospective reports. However, the immediate post-legalization timeframe (April 2024) captures only acute behavioral responses; longer-term effects remain unknown. The study contributes valuable preliminary insights into how legal reforms influence consumption patterns in real-world contexts, informing future policy and prevention strategies, though findings require confirmation in larger, more diverse populations with extended follow-up periods.

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