Alcohol can indeed contribute to aggression, but it's important to understand the mechanisms at play. Alcohol tends to decrease activity in the sympathetic arm of the autonomic nervous system, which makes us feel less alert. However, initially, it can create a state of alertness by inhibiting the forebrain, particularly the prefrontal cortex, which normally exerts a quieting effect on some circuits of the hypothalamus. This reduction in inhibition can lead to increased overall activity, causing us to talk and move more than we normally would.
As alcohol levels increase, it starts acting as a sedative, reducing activity in the forebrain and releasing deeper brain circuits involved in impulsivity. This can lead to increased impulsivity, but through a different mechanism than substances like caffeine. A study published in the Journal of Addictive Behavior in 2016 found that the more alcohol someone consumed, the more likely they were to engage in indirect aggressive behaviors, such as verbal acts of aggression.
So, while alcohol doesn't directly cause aggression, it can create conditions in the brain that make aggressive behavior more likely.