Study: Smoking weed linked to aggression

INDIANAPOLIS (WISH) – Results from a study spanning over five decades found a relationship between marijuana use and violent behavior.

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The findings, published in Psychological Medicine, is in contrast with other literature associating smoking with feelings of peacefulness and relaxation.

Investigators at King’s College in London followed 411 males between the ages of eight and fifty-six years old beginning in 1953 observing them for over 50 years for the purpose of assessing the connection between long-term cannabis use and violence. Violence was defined by two outcomes: criminal convictions and self-reported data.  

Results showed males who smoked weed were 7.1 and 8.9 times more likely to exhibit violence as measured by criminal convictions and self-report compared to those who never smoked. Although the mechanism underlying the relationship is not yet known, lead author Tabea Scholer, MSc speculate the drug may cause “impairments in neurological circuits controlling behavior” This may result in altered neural functioning in a specific part of the brain called the ventrolateral prefrontal cortex, Scholer said in a previous interview.

The ventrolateral prefrontal cortex area is responsible for decision making and behavior inhibition.

“These results provide strong indication that cannabis use predicts subsequent violent offending, suggesting a possible causal effect,” authors say in the paper. This evidence may help public health policy makers with issues surrounding marijuana use, they add.