Why Does Alcohol Make Some People Aggressive?

Alcohol effects people differently. Some people become more fun, some fall asleep, some feel depressed, and some get ugly. Intoxication alone does not cause violence. Not everyone who drinks will become aggressive, but alcohol may increase the risk of violence for some people in some situations.

Some people believe that liquor causes them to behave badly, whereas beer is not problematic. The issue is not the source of the alcohol, but the level of alcohol in your system. Whether it is beer or liquor, rage can begin after one drink or after a number of drinks. Alcohol, along with several other factors, can put you at risk for aggression.

Biology is one factor for aggression. Alcohol may encourage aggression or violence by disrupting normal brain function. The executive command center (prefrontal lobe) is dulled. This is the area of the brain that controls decision-making, problem solving and reasoning. Without this brain function, it becomes harder to self-regulate.

Alcohol alters the way you process information and impairs your ability to assess other’s intentions. When drunk, your perspective changes and you lose your reasoning skills. You may attribute great harm in situations where there is little actual threat. And when drunk, you give less thought to the consequences of your behavior. When sober, you may think twice about punching out someone who offended you but when drunk you may not restrict your impulses.

Drinkers with lower levels of serotonin and higher levels of testosterone are more prone to violence. Decreased serotonin is associated with poor impulse control and aggressiveness. High testosterone is associated with violence and hostility. Adolescent and young adult males tend to have higher levels of testosterone compared to the general population. Men become less aggressive when they reach their forties. At that age, testosterone is decreasing and serotonin is increasing, both factors that inhibit violent behavior. (1990 study done by Brown & Linnoila)

Personality is another factor for aggression. Some people are already prone to anger and violence, and adding alcohol can exacerbate the situation. Abuse of alcohol and a propensity to violence may stem from a personality trait such as a risk-seeking personality or anti-social personality disorder. People who have difficulty controlling their anger when sober will have even more difficulty controlling it when drunk.

A third factor is social expectations. Aggressive behavior tends to be condoned in situations in which violence occurs frequently, such as in bars or sporting events. People who believe they have consumed alcohol begin to act more aggressively (1994 study by R. Gustafson).

Most people who drink do so responsibly and cause no negative consequences. Yet a minority of people who become aggressive cause a safety threat to others. 85% of homicide offenders were drinking at the time of their offense. 37% of assault offenders, 60% of sexual offenders, up to 57% of men and 27% of women involved in domestic violence, and 13% of child abusers were drinking at the time of their offense. Identifying who is at risk for alcohol related violence will help those whose violence has caused trouble for them and others.