A meta-analysis by British researchers has revealed a significant correlation between cannabis use and an increased risk of violence, both in inflicting and experiencing violence. The findings were published last month in the journal Psychological Medicine and were authored by a team of researchers from the United Kingdom.
The researchers analysed 63 studies on cannabis, which together involved more than 265,000 participants. The key finding of the study is that users of cannabis are statistically more likely to commit violent acts, and it was found that drug use, particularly among women and in mixed-gender groups, was significantly associated with an increased risk of becoming a victim of violence.
The link between cannabis use and violence was more pronounced among psychiatric patients. Previous research has indicated that individuals with existing mental disorders, such as psychosis, may experience worse clinical outcomes if they continue to use cannabis. Given the higher rate of cannabis use among people with severe mental disorders compared to the general population, this group represents a particularly vulnerable population in terms of violent behaviour.
The researchers found that cannabis users may be exposed to risky situations, which could explain the increased vulnerability to violence. Users of cannabis may be exposed to peers who use opioids or are involved in criminal activities.
The study’s co-author, a professor at King’s College London, stated that as a clinician, she had witnessed how intensive cannabis use could be a factor in violence. The co-author, a professor of psychiatric research at King’s College, Sir Robin Murray, stated that as cannabis becomes increasingly commercialised and legalised around the world, the debate surrounding its risks has largely focused on the individual user. This review highlights that violence, whether as perpetrator or victim, must also be part of that discussion, he added.
The researchers emphasise that this is a correlation, not necessarily a causal relationship. They do not claim that the drug directly causes violence, as there is no scientific consensus on the matter. The results highlight the importance of addressing this issue at both a societal and clinical level.
The researchers suggest that violence should be considered alongside other identified harms associated with cannabis when developing prevention strategies, public education campaigns, and regulatory policies. The study also highlights the need for mental health professionals to routinely assess cannabis use in individuals showing signs of violent tendencies, particularly those with severe mental illnesses.
Future studies will need to untangle causal pathways through more detailed research into why, when, and how people use the drug. Other studies should examine whether reducing cannabis consumption through clinical or public health interventions leads to a reduction in violent behaviour.
