Alcohol intoxication amplifies feelings of aggression while cannabis intoxication diminishes feelings of aggression, according to research published in Psychopharmacology.

The study of 61 participants found alcohol consumption increased aggressive responses during a computer-based experiment designed to measure aggression, while cannabis consumption reduced aggressive responses.

PsyPost interviewed the study’s corresponding author, Elizabeth de Sousa Fernandes Perna of Maastricht University. Read her responses below:

PsyPost: Why were you interested in this topic?

We wanted to investigate the link between alcohol, cannabis and aggression in healthy individuals who regularly consume alcohol or cannabis. Alcohol consumption has long been associated with acts of aggression and violence, whereas cannabis use is not typically associated with aggression. We were primarily interested to see how alcohol and cannabis would acutely affect subjective feelings of aggression next to physical acts of aggression when exposed to aggression stimuli.

What should the average person take away from your study?

It is important to keep in mind that while alcohol intoxication can increase feelings of aggression in regular alcohol users, it does not automatically mean that it will lead to behavioral acts of aggression in a real-life setting. The same is true for cannabis, but vice versa, cannabis intoxication does not automatically lead to a reduction of aggressive behavior in regular cannabis users. The results of our study indicate that intoxication with alcohol is more likely to lead to aggression compared to cannabis intoxication.

Are there any major caveats? What questions still need to be addressed?

We have shown that aggressive feelings were enhanced following an alcohol dose of 0.8 g/kg and we have also observed that aggressive responses increased with heightened feelings of aggression. However we cannot conclude that a higher alcohol dose is more likely to cause physical aggression as we did not investigate the effect of varying alcohol (or cannabis) doses on aggression. It is also interesting to see if the interaction between alcohol or cannabis intoxication and aggression exposure would be different when looking at males and females separately. Previous studies indicate that men are more likely to become aggressive when drunk, but is this also the case when both genders are exposed to aggression stimuli?

Is there anything else you would like to add?

Future studies investigating the drug-aggression relation should investigate the interaction between different risk factors that are associated with aggression, such as consumption patterns of alcohol and drug use, combined with neuroendocrine measures, such as testosterone and cortisol ratios, and genetic markers. Other factors that also play an important role are personality traits and personal expectations about the effects of alcohol.

Examining these interactions can help us identify healthy individuals who are at risk of engaging in ‘intoxicated aggression’ more effectively when exposed to aggression stimuli.

The study, “Subjective aggression during alcohol and cannabis intoxication before and after aggression exposure“, was also co-authored by E.L. Theunissen, K.P.C. Kuypers, S.W. Toennes, and J.G. Ramaekers.