Alcohol is a central nervous system depressant that affects brain function. When someone drinks more than their body can handle, it can result in slurred speech, loss of coordination, blurred vision, slowed reaction time, impaired judgment and decision-making abilities. This intoxicating effect also lowers inhibitions and impairs emotional regulation, which can lead to aggressive, argumentative or mean behavior in some people.
How alcohol affects the brain
Alcohol inhibits brain centers that control judgment and processing of sensory information. It also increases levels of dopamine, a neurotransmitter associated with pleasure and sociability. At moderate levels of consumption, these brain changes can make people feel more relaxed, sociable and happy.
However, at higher blood alcohol concentrations, alcohol begins to affect the prefrontal cortex of the brain. This is the area responsible for rational thinking, impulse control and regulating emotions. When alcohol inhibits prefrontal cortex functioning, people lose the mental ability to suppress behaviors or attitudes they might normally restrain when sober.
In addition, alcohol triggers the release of adrenaline, the “fight or flight” hormone. Adrenaline increases aggression, arousal and risk-taking tendencies. This combination of disinhibited behaviors and emotions can generate belligerent, risky or violent behaviors in intoxicated individuals.
Factors that influence reactions to alcohol
While alcohol has predictable effects, reactions can vary based on:
- Amount consumed – Higher blood alcohol levels cause more intense reactions.
- Genetics – Variations in genes affect alcohol absorption and brain chemical responses.
- Age and sex – Younger people and females tend to be affected more.
- Food intake – Eating before or while drinking slows absorption.
- Tolerance – Chronic heavy drinkers tolerate more alcohol before showing effects.
- Mood – Pre-existing stress, anxiety or sadness enhances alcohol’s effects.
- Environment – Noisy, provocative settings can trigger aggression.
- Drugs – Combining alcohol with medications or illicit drugs intensifies effects.
These variables help explain why some people experience mellow or sleepy reactions to alcohol, while others become more animated and lose control over their words and actions.
Disinhibition and aggression
Alcohol reduces social inhibitions through its effects on the prefrontal cortex. Inhibitions are mental mechanisms that restrain impulses, maintain standards and regulate socially appropriate behavior. When alcohol restricts the prefrontal cortex, people become more talkative, emotionally reactive and quick to act without consideration.
This disinhibition effect also allows suppressed or unconscious urges and emotions to surface. People are more likely to say and do things that they would normally keep private or to themselves when sober. They may act provocatively, pursue sexual encounters, engage in risky behaviors, become verbally aggressive or seek confrontations.
Factors that contribute to alcohol-related aggression include:
- Irritability – Alcohol increases heart rate and sweating, making people more irritable and quick-tempered.
- Testosterone – Alcohol elevates testosterone, the male hormone linked to dominance and aggression.
- Peer pressure – Being around other intoxicated, loud people can trigger aggressive acts.
- Misperceptions – Alcohol impairs information processing and judgment, increasing the potential for misunderstandings, offense or conflict.
- Expectations – Believing alcohol makes you aggressive or horny can be a self-fulfilling prophecy.
- Stress relief – Some drink as an unhealthy coping method to temporarily escape problems.
Alcohol enables aggression by removing mental blocks against it. But the specific triggers that cause someone to direct anger or meanness towards a certain target or situation depends on many psychological, cognitive and social factors.
Mean vs. violent behavior
Most people who become verbally nasty or mean when drunk are not looking for fights or intending harm. However, as they lose inhibitions, they are more likely to say insensitive or rude remarks, express contentious viewpoints, insult others, shout and become belligerent. They essentially stop filtering their thoughts.
Occasionally, intoxicated people cross the line from simply being mean to committing violent acts against others or property. Their risk of violence rises when they combine heavy drinking with anger issues, drug abuse, gun ownership or other dangerous mixes.
Research shows that more than half of victims who suffer alcohol-related violence knew their offender. Spouse abuse, drunken brawls between friends and alcohol-fueled assaults often erupt from arguments, mutual insults or misunderstandings while impaired.
Blackout drunkenness
Many cases of alcohol-induced mean behavior occur during blackout states. Blackouts describe amnesia for events that happened while drunk. The drinker is awake and actively engaging in behaviors, but the brain does not form memories for the period.
Blackouts are caused by very high blood alcohol levels that drastically impair cognitive functioning, short-term memory and ability to store recollections. Research suggests that over 50% of college drinkers have experienced a blackout.
Waking up the “morning after” and being told of one’s verbal abusiveness, reckless behaviors or sometimes even violent actions during the forgotten blackout can be shocking and distressing. However, not being able to recall mean words or deeds does not absolve responsibility for the harm caused.
Preventing alcohol-induced meanness
It’s unrealistic to expect people will stop drinking entirely. But there are steps one can take to reduce the odds of alcohol turning someone mean:
- Pace drinking and stay below binge levels.
- Avoid hard liquor and stick to lower alcohol brews like beer.
- Eat a full meal before drinking to slow absorption.
- Alternate alcoholic drinks with water or juice.
- Have no more than one drink per hour.
- Don’t mix alcohol with drugs.
- Make sure you expect to stay mellow, versus assuming liquor will make you mad or wild.
- Avoid provocative environments and drunk people when intoxicated.
Because alcohol affects people differently, the only sure way to prevent drunken nastiness is to not drink at all or to keep consumption minimal. For some, abstinence is wisest. If drinking does make you repeatedly mean or aggressive, seek help to change your habits or better manage the anger issues influencing your behavior.
Conclusion
Alcohol can transform someone’s personality and behavior in ways they later regret by disabling brain regions that normally restrain impulses and negative emotions. While most intoxicated people become more talkative, silly or carefree, some experience enhanced aggression, risk-taking, meanness and combativeness when disinhibited by liquor. Understanding how alcohol biologically alters moods, reactions and inhibitions helps explain this phenomenon.