Brief
Review links cannabis use to higher risk of violence and victimisation
Researchers at King's College London report increased odds of both perpetrating and experiencing violence among cannabis users.
By Felo News Desk · Published
A review of 63 studies involving more than 265,000 people, led by researchers at King's College London, found that cannabis users are about twice as likely to commit violent acts and 1.5 times as likely to be victims of violence, according to the study published in Psychological Medicine.
What happened
The team from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) analysed data from the general population and from psychiatric patients separately. Using the World Health Organization’s definition of violence, they examined physical, sexual and psychological aggression, both inside and outside intimate relationships, and distinguished self‑reported incidents from criminal convictions.
What the reports add
In the general population, cannabis users were roughly twice as likely to have committed a violent act as non‑users. Among psychiatric patients, the odds rose to about two‑and‑a‑half times compared with non‑using patients. The association persisted in longitudinal studies, though it was weaker than in cross‑sectional studies. For violence that led to a criminal conviction, the risk increased three‑ to four‑fold.
What was said
Dr. Marta Di Forti, co‑author of the study, told ScienceDaily, "As a clinician, I've seen how heavy cannabis use can be a factor in violence… a review of this size lets us 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, added, "In the general population, people who used cannabis were around twice as likely to have committed a violent act as those who didn't; for those in psychiatric care, cannabis users were around two and a half times as likely to be violent as other psychiatric patients who didn't use cannabis."
How it came about
The review builds on earlier epidemiological work linking substance use to aggression, and comes as cannabis becomes increasingly commercialised and legalised in many jurisdictions.
Key facts
- The review covered 63 studies with over 265,000 participants. (sciencedaily.com)
- Cannabis users were about twice as likely to commit violence in the general population. (sciencedaily.com)
- Among psychiatric patients, cannabis users were roughly 2.5 times more likely to be violent. (sciencedaily.com)
- Cannabis users were 1.5 times more likely to be victims of violence, with a stronger effect in women. (sciencedaily.com)
- Risk of a criminal conviction for violent acts was three to four times higher for cannabis users. (sciencedaily.com)
Sources
- [1] sciencedaily.com — originally reported as “Cannabis users were twice as likely to commit violence, review finds”
