Cannabis users were twice as likely to commit violence, review finds

A large review led by researchers at King's College London has found that people who use cannabis are more likely both to commit violent acts and to experience violence themselves.

Researchers from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) combined data from 63 studies involving more than 265,000 people. They analyzed the general population separately from people receiving psychiatric care.

The researchers used the World Health Organization's broad definition of violence, which includes physical, sexual and psychological violence toward another person, both inside and outside intimate relationships.

They also separated self-reported violence from cases that resulted in criminal convictions. When individual studies measured several forms of violence, the researchers focused on the most serious type reported. The findings were published in Psychological Medicine .