By / October 10, 2019

Debate: Do cannabis and violence have a connection?

The connection between cannabis and violence generated a controversial debate among specialists in the United States.

The controversy started when former FOX News host Tucker Carlson interviewed Alex Berenson, a former New York Times reporter.

Berenson also published the book “Tell Your Children: The Truth About Marijuana, Mental Illnesses, and Violence”.

Why Berenson believes marijuana cause psychosis

Berenson argues that marijuana causes psychosis, and psychosis causes violence, resulting in the conclusion that marijuana causes violence.

That claim was based primarily on two studies connecting marijuana use with psychosis.

Some researchers have found connection between cannabis and violence as woman smokes in room.
At this point, researchers emphasize having found an association between marijuana and psychosis, but that is not the same as claiming that marijuana causes psychosis. (Source)

The first analysis was conducted in 1987. It concluded that cannabis is responsible for 10-15% of cases of schizophrenia. It also concluded that this disease triggers violent acts.

The National Academies of Science, Engineering, and Medicine in the United States conducted the second study in 2017. Its results stated that cannabis use may increase the risk of developing schizophrenia and other psychoses.

With this in mind, Berenson reaffirmed his theory by using the behavior of the mass shooter in Dayton, Ohio. The shooter had been a long-time marijuana user.

Psychosis, cannabis and violence

British and Dutch researchers support this decision through a study. It revealed that marijuana increases violent behavior, but in people who already suffered from psychotic disorders such as schizophrenia.

At this point, researchers emphasize that while they have found an association between marijuana and psychosis, it is not the same as claiming that marijuana causes psychosis.

Dr. James Knoll, director of forensic psychiatry at Syracuse University, discovered higher marijuana use among young men, people with serious adverse childhood experiences, antisocial personality, low income, low education and those who use other illicit substances.

Smoking marijuana doesn’t make you violent

Katherine Newman is an internal chancellor at the University of Massachusetts and author of a book on school shootings.

Newman told PolitiFact that the idea of marijuana use leading to violence is absolute nonsense since there is no link between marijuana and extreme violence.

Cannabis and violence may not go hand in hand - it may be like this photo, filled with music.
Hansen said that people with mental disorders who use marijuana are more likely to resort to it in an effort to medicate themselves. (Source)

Ziva Cooper of UCLA, a member of the study board, questioned Berenson’s findings. She tweeted she did not conclude that cannabis causes schizophrenia. However, she found an association between this disease and people who smoke cannabis.

Benjamin Hansen, professor of economics at the University of Oregon, is another of the specialists who refutes the connection. He built a model to estimate what the murder rates in Colorado and Washington would look like if marijuana had not been legalized.

He wrote that the homicide rates in Colorado and Washington were actually below what the data predicted between 2000-2012.

Mark Kleiman, professor of public policy at Wagner University of New York, gave another view. He stated that excessive cannabis use in the United States has increased since 1992.

However, from that date to the present, national homicide rates have fallen by more than 50%. Hansen said that people with mental disorders who use marijuana are more likely to resort to it in an effort to medicate themselves.

A connection between cannabis and violence?

Despite the scientific endorsements, this series of statements only promotes disinformation, since so far, none of the studies are relevant.

It is not possible to legally administer marijuana in a controlled laboratory environment, so researchers can not determine whether or not its use generates some behavior of violence.

(Featured Image by Nathan Cowley)

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