Cannabis use linked to violence, but evidence remains uncertain
A large review found an association, yet methodological limits mean the link is far from settled.
16 Oct 2026 0 reads Compiled with AI
A systematic review of 63 studies involving more than 265,000 people found a statistical link between cannabis use and violent behaviour, but the headline of a recent article exaggerated the certainty of that finding.
The review’s strongest association came from cross‑sectional studies that measured use and violence at the same time; those studies reported odds of violence more than twice as high for users, whereas longitudinal studies that followed people over time showed only a 17 % increase. The difference illustrates how study design can shape results.
Multiple potential biases—confounding factors such as poverty, alcohol use, or a difficult upbringing; variation in how studies defined cannabis use and violence; and the possibility that studies with null results are less likely to be published—reduce confidence. The authors rated the certainty of the evidence as very low, meaning the true size of the association is far from known.