A joint, an edible, a vape pen—and a troubling new finding.
Cannabis users were about twice as likely to report committing violence as people who did not use cannabis, according to a sweeping review that pulled together data from 63 studies involving more than 265,000 people.
The same review found users were also more likely to land on the other side of the equation: they had about 1.5 times the odds of experiencing violence themselves.
But don’t twist the headline into “pot makes people violent.” The research found a strong association, not proof that cannabis alone caused anyone to hurt another person. Alcohol, other drugs, trauma, serious mental-health symptoms, unstable housing, financial pressure, relationship conflict, and past exposure to violence can all be part of the same picture.
The numbers that grabbed attention
The review, published in Psychological Medicine, separated the general population from people receiving psychiatric care.
In general-population studies, cannabis users had about double the odds of reported violent behavior compared with nonusers. Among psychiatric patients, cannabis use was linked to roughly 2.5 times the odds of violence compared with patients who did not use cannabis.
The association was smaller, but still statistically significant, in studies that followed people over time: users had 1.17 times the odds of subsequent violent behavior. That matters because it suggests the connection didn't disappear when researchers looked beyond a one-time snapshot. It does not prove cannabis was the cause.
Then came the most explosive number.
For violence that resulted in a criminal conviction, cannabis users had about 3.75 times the odds in general-population studies and about 4.21 times the odds among psychiatric patients. Those figures should be handled carefully: criminal-conviction outcomes were available from fewer studies, and a conviction can reflect more than just behavior—it can also be shaped by policing, reporting, charging, courts, and other social factors. cambridge
This is not a “pot causes violence” verdict
Here is the part that gets lost in a fast-moving headline: studies like these cannot hand researchers a clean answer to the question of cause.
Someone who uses cannabis may also be drinking heavily, using other substances, dealing with untreated mental illness, recovering from trauma, sleeping poorly, living under intense stress, or spending time in unsafe environments. Those factors can raise the risk of violence, victimization, or both.
Cannabis use may be part of that broader risk mix. It may also be used by people already trying to cope with distress, anxiety, trauma, pain, or unsafe circumstances. The review cannot fully untangle which factor came first, which factor drove the result, or how much each one mattered.
That is why the responsible takeaway is not “cannabis turns people violent.” It is that cannabis use showed up repeatedly alongside a higher rate of violence in a very large body of research—and that connection deserves serious, nonjudgmental attention.
What did researchers mean by “violence”?
Not just headline-grabbing assaults.
The researchers used the World Health Organization’s broad definition of violence, which can include physical, sexual, and psychological harm, whether it happens in an intimate relationship or elsewhere.
The 63 studies were not carbon copies of one another. Some relied on self-reported behavior. Some used criminal-conviction records. Some examined specific forms of violence, while others used broader measures. When studies measured more than one kind of violence, the reviewers focused on the most serious outcome reported.
That broad approach allowed the team to look across a huge amount of research. It also means the result is not a simple “cannabis equals crime” scorecard. Different studies defined use, violence, timing, and risk differently.
Users were also more likely to be victims
The review’s other uncomfortable finding is that cannabis users were not only more likely to be reported as perpetrators—they were also more likely to report being harmed.
Across the studies, cannabis use was associated with about 1.49 times the odds of violence victimization. The association was more pronounced in women and in mixed-gender study groups than in male-only groups.
That does not mean cannabis causes victimization, and it should never be used to blame a victim for being harmed. The finding may reflect overlapping risks: substance use, unsafe relationships, trauma, poverty, neighborhood violence, coercion, mental-health challenges, or exposure to people who are using substances heavily.
But it does underline a point that gets overlooked in the cannabis debate: the risks connected to use may extend beyond the user and into their relationships, homes, and communities.
The psychiatric-care finding needs care
The strongest overall association appeared in studies of people receiving psychiatric care. That fact needs context—not stigma.
Psychiatric patients are not inherently dangerous, and most people living with mental-health conditions do not commit violence. Equally, most people who use cannabis do not commit violence.
Still, for a clinician assessing someone’s safety, cannabis use may be one relevant question among many: What other substances are involved? Are there symptoms of paranoia, mania, severe depression, psychosis, agitation, impulsivity, trauma, or sleep deprivation? Is there relationship conflict, access to weapons, threats, or a history of harm?
The review’s authors argue that cannabis use should be assessed routinely in psychiatric settings as part of a broader risk evaluation. That is not about branding someone as dangerous. It is about understanding the full situation before trouble escalates.
Today’s high-THC pot is still a big question mark
The studies in the review covered a long period, and much of the underlying research was conducted before today’s high-potency products became common in many markets.
That matters because a 2026 cannabis concentrate, vape cartridge, or high-THC edible may bear little resemblance to the lower-potency products used in older studies. But the review cannot tell us whether modern products are more closely associated with violence, because only a small number of studies measured dose, frequency, or potency.
The authors did not establish whether daily use carries a different risk than occasional use. They did not establish a THC threshold. They did not establish whether smoking, vaping, edibles, concentrates, or synthetic products differ. And they did not establish that higher potency causes more violence.
Those gaps are not evidence of safety or danger. They are a sign that research has not caught up with a rapidly changing commercial cannabis market.
What this means for families
The study does not mean a parent, partner, friend, or coworker should panic because someone uses cannabis.
But it may be worth taking the conversation seriously when cannabis use appears alongside warning signs such as:
- A sharp change in mood, behavior, sleep, or judgment
- Heavy or escalating use
- Mixing cannabis with alcohol or other drugs
- Increasing paranoia, severe anxiety, agitation, or suspiciousness
- Threats, controlling behavior, frequent explosive conflict, or fear in a relationship
- Work, school, financial, legal, or family problems connected to use
- Using cannabis primarily to numb trauma, distress, or overwhelming emotions
A calm conversation, support from a healthcare professional, substance-use counselor, or mental-health clinician, and attention to immediate safety can be more useful than shame, confrontation, or labels.
If someone has made threats, has access to weapons, is severely agitated or confused, or you believe immediate harm may occur, seek emergency help right away.
Legal does not mean risk-free
As cannabis becomes legal or commercially available in more places, public conversation often centers on individual choice, tax revenue, criminal-justice reform, pain relief, or medical access.
Those are real issues. So are potential harms.
Legal status does not make any substance harmless for every person, in every amount, or in every context. The same is true for alcohol, prescription sedatives, stimulants, and many other substances. A more mature conversation about cannabis has room for both realities: many people use it without becoming violent, and large-scale research has identified associations that public-health and mental-health professionals should not ignore.
The bottom line
This review found that cannabis users had higher reported odds of both committing violence and experiencing it. The link was seen across 63 studies involving more than 265,000 people, and it remained present—though smaller—in research that tracked people over time.
That is a serious public-health signal. It is not proof that cannabis causes violence, a prediction of what any one user will do, or a license to stereotype people who use cannabis.
The smartest reading is also the toughest: cannabis may be one factor in a complicated web involving other substances, mental health, trauma, poverty, relationship safety, stress, and social conditions. Researchers now need stronger studies that track timing, frequency, THC potency, co-use of alcohol and other drugs, psychiatric symptoms, and real-world environments before they can say what is driving the association.
Medical and safety disclosure: This article is for general educational and informational purposes only. It is not medical, mental-health, or legal advice. If cannabis use feels hard to control, is affecting mood, relationships, work, school, safety, or daily functioning, consider speaking with a qualified healthcare or mental-health professional. If you are in immediate danger, think you may harm someone, or fear someone may harm you, call emergency services or a local crisis resource immediately.
