Cannabis Users Twice as Likely to Commit Violence: Review — SkimNews

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- King's College London researchers combined 63 studies covering more than 265,000 people, finding cannabis users were about twice as likely to commit violent acts in the general population and 2.5 times as likely among psychiatric patients.
- Cannabis users with criminal convictions for violence were three to four times as likely to have been convicted; the link held in longitudinal studies but was smaller than in cross-sectional designs.
- Cannabis users were about 1.5 times as likely to become victims of violence, with the association stronger among women than men, using the WHO definition covering physical, sexual, and psychological violence.
- Dr. Marta Di Forti of King's IoPPN said the review lets researchers 'speak with more confidence about the risks, while being careful not to stigmatize people who use cannabis more broadly.'
- Professor Sir Robin Murray, senior author, argued that as cannabis becomes more commercialized and legalized, the public conversation 'has focused mostly on the person using it' and must now include both perpetration and victimization.
- The researchers caution the review identifies an association, not causation, and note cannabis use often co-occurs with alcohol, other drug use, and difficult social circumstances that also elevate violence risk.
- The study, published in Psychological Medicine and funded by the NIHR Maudsley Biomedical Research Centre and MRC, drew on research mostly conducted before today's high-potency cannabis products became common — a limitation the authors flag.
Why it matters: The researchers are calling on mental health services to routinely ask about cannabis use when assessing violence risk, and on public health messaging to include the violence link — though they stress this is correlation, not proof cannabis itself causes violent behavior.
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