The Impact of British Columbia's Drug Decriminalization Policy on Police-Reported Drug Possession Seizures

British Columbia, Canada, implemented a 3-year pilot that decriminalized the personal possession of select illegal drugs beginning January 31, 2023. The policy was amended to prohibit drug possession in all public spaces starting May 7, 2024. The impacts of decriminalization and the subsequent decriminalization amendment on police-reported drug possession seizures were examined; these seizures were identified on the basis of incidents in which drug possession offences were recorded as the most serious offence.

Monthly, population-based crude rates of police-reported drug possession seizures of any quantity and police-reported drug possession seizures involving up to 2.5 grams were analyzed using an interrupted time series design with generalized additive models (January 2019-July 2025; data were collected and analyzed in 2026). The models tested level changes in the outcomes associated with the initial decriminalization policy and the subsequent decriminalization policy amendment relative to the predecriminalization.

Decriminalization relative to predecriminalization was associated with a 68% decrease in police-reported drug possession seizures of any quantity (β= -1.1, 95% CI= -1.4, -0.9). However, police-reported drug possession seizures of any quantity increased after the decriminalization amendment, such that they were statistically indistinguishable from predecriminalization levels (β= -0.2, 95% CI= -0.6, 0.1). A similar pattern of findings was observed for police-reported drug possession seizures involving up to 2.5 grams: decriminalization relative to predecriminalization was associated with an 87% decrease (β= -2.0, 95% CI= -2.5, -1.6), whereas the decriminalization amendment relative to predecriminalization status was not associated with significant changes (β=0.4, 95% CI= -0.2, 1.0).

Decriminalization was associated with decreases in police-reported drug possession seizures of any quantity and police-reported drug possession seizures involving up to 2.5 grams. The subsequent decriminalization amendment reversed this trend because both types of police-reported drug possession seizures returned to levels comparable to those observed before decriminalization.