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4 min read

What Exactly Does Alcohol Do to Your Brain?

alcohol bottle graphic

We can use the timeline of human history to make inferences about our priorities as a species. As it happens, we pretty much invented houses, then alcohol, and then everything else.

Here's a list of things that were invented after alcohol:

  • Democracy
  • Compasses
  • Gunpowder
  • Windmills
  • Usable iron
  • Sailing
  • Irrigation

The first known use of alcohol occurred in the Yellow River Valley about 8000 years ago. Some scientists discovered the residue of a fermented beverage containing honey, rice, and a fruit (likely hawthorn fruit or grapes). It's no crisp chardonnay, but apparently it did the trick because it really caught on.

Nowadays, humans produce enough alcohol every year to fill over 3,000 Walmart Super Centers, wall to wall and floor to ceiling.

You could argue that nothing has been so popular (or indeed has such a profound effect) on our global culture as alcohol.

But why? What exactly does alcohol do to our brains? How does it have such a deep hold on us that nearly a quarter of every song we write as a species mentions it?

Let's explore.

During Drinking: How Alcohol Makes You Feel Buzzed or Drunk

After Drinking: What Causes Hangovers?

Why Is Alcohol So Addictive?

During Drinking: How Alcohol Makes You Feel Buzzed or Drunk

First, let's get some science out of the way.

When you consume a small amount of alcohol (like a sip), your liver breaks it down into acetaldehyde, and then into acetic acid. Then you pee it out.

When you consume larger amounts of alcohol, your liver can't work fast enough, and some of the alcohol makes its way to your brain. This starts a number of chemical processes that all have different effects, but the two most immediately noticeable are:

  • A surge in dopamine, your brain's "feel-good" chemical.
  • An increase in the effects of something called gamma-aminobutyric acid, or GABA.

An inhibitory neurotransmitter, GABA is normally responsible for keeping our neural activity in check. Without it, you would basically go into the world's worst-ever seizure and then promptly die. Too much of it (or, in this case, too much sensitivity to it) and every cognitive process slows way down.

These chemical processes create the sensation of being drunk.

Why Alcohol Can Make You Feel More Confident

When the effect of GABA is heightened, its first noticeable effect occurs in your limbic system.

Your limbic system is composed of several little glands and organs and is responsible for controlling your emotional responses. When you get drunk and GABA begins to slow down your limbic system, your brain is no longer registering emotional stimuli correctly.

That's why, after a few drinks, you feel like you can muster up the courage to ask a guy out. Your limbic system is no longer registering the fear of rejection as an important social and emotional process.

It's also why, after many, many drinks, people tend to get a bit... well, stupid. At a certain level of alcoholic toxicity, your inhibitions disappear entirely. Without your limbic system telling you, "Hey, maybe you shouldn't be insulting this muscled biker's leather jacket," you can get yourself into trouble.

Alcohol Also Reduces Motor Coordination

Your cerebellum - the bulbous thing tucked behind your brain stem - keeps your hands and feet moving the way you want them to.

When it slows down due to alcohol consumption, you might begin stumbling or falling. Not only is this highly embarrassing, but it can also cause further injury.

Dopamine Release from Alcohol Consumption

When you have a few drinks, your dopamine surges, which, in moderation, can make you feel calm and happy.

It's worth noting that this is a temporary and unsustainable response and contributes heavily to alcohol's severely addictive nature. But more on that later.

After Drinking: What Causes Hangovers?

Contrary to what the labels say on an assortment of mysterious gas station pills, no one is exactly sure of what specifically causes hangovers.

In all likelihood, a "hangover" is actually a collection of several problems related to drinking.

Low Blood Sugar

Your liver's primary job is to filter and clean your blood, but it also regulates the level of glucose (sugar) in your blood, which your body then uses to energize many of its processes.

When you get drunk, your liver has to make a choice: make sugar available, or get rid of the immense volume of toxic material it's suddenly encountering. Because low blood sugar usually just makes you tired and grumpy, while toxins have a tendency to kill you, it chooses the latter.

That's one of the reasons you're so sapped of energy the day after a night out.

Lack of Quality Sleep

Numerous studies associate high alcohol consumption with poor sleep quality.

The theory as to why has to do with your brain's response to alcohol over time.

In a normal night's sleep, you go through several rapid-eye movement cycles, which is when the good sleep happens.

After a night of drinking, the first few cycles are interrupted because your brain is slowed down, preventing REM sleep.

Then, as the alcohol wears off, your brain kicks into repair mode and keeps your sleep light and inefficient.

Interestingly, this happens even after one or two drinks. If you're a consistent nighttime drinker - even a light one - and you're finding that you're always fatigued, consider skipping the Bud Light for a few days and see how you feel.


Alcohol has a diuretic effect on your kidneys, which means it makes you pee a lot. During a busy night out where you forget to drink water, this can lead to dehydration.

Being dehydrated screws with pretty much everything your body does to keep you regulated.

Vomiting, Headaches, and Soreness

Chemically, alcohol is basically poison. After drinking a lot of it, your body is going to respond accordingly.

When you get drunk, your stomach produces more acid to try and combat your consumption. This can lead to nausea and vomiting.

Your immune system activates when you get drunk, causing general inflammation and soreness as well as cognitive issues like fatigue and confusion.

Alcohol is also vasoconstrictive, tightening the blood vessels in your brain and giving you that splitting headache.

Hangovers, then, are a nasty and painful - but very clear - message from your body: You overdid it, and now we have to pick up the pieces.

There is no cure-all for a hangover, but you can theoretically shorten it by giving your body what it needs to fix itself. Drink a few glasses of water, have an apple, and go back to bed.

Why Is Alcohol So Addictive?

Alcohol's addictive nature is heavily related to the way it releases dopamine in your brain.

It's a similar mechanic to many other addictions, like those to cocaine or meth. Here's the general order of operations:

  • You get drunk, and your brain releases large amounts of dopamine.
  • Your brain then automatically adjusts its production of dopamine to try and keep things constant. This means it will naturally produce less dopamine temporarily after a night of drinking.
  • In order to feel normal, you'll need to artificially raise your dopamine levels again with whatever you have on hand - usually alcohol.
  • Multiply this process over a long period of heavy drinking, and you'll begin to rely on alcohol for most of your sustained dopamine.
  • You are now addicted to alcohol.

In short, alcohol is like most things: you have to moderate. With the exception of recovering addicts, for whom drinking any alcohol is extremely dangerous, most people can have a few drinks a week with minimal adverse long term effects.

But if you find yourself beginning to crave alcohol, consistently binge drinking, or feeling irritable when you don't have access to alcohol, you should stop drinking and talk to a psychiatrist or doctor.

Book a Psychiatry Appointment


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