The effects of alcohol
- You need to be 18 years or older to drink alcohol.
- Alcohol affects us in different ways, so it’s worth learning how it works.
- It’s poisonous and messes with your nervous system.
- It has consistent physical and mental effects, reducing our ability to perform complex tasks.
- Its social, emotional and behavioural effects vary, and are influenced by a combination of social norms and expectations, as well as environmental factors.
One molecule to mess you up
Alcohol is so common but affects us in such different ways, it’s worth learning about how it works:
- To begin with, there are a number of molecules called alcohols, and they are all poisonous to humans. For some alcohols, doses of more than a few millilitres will kill you.
- When we talk about alcohol as something you can drink, we’re talking about one specific alcohol molecule, called ethanol.
- Like the other alcohols, ethanol is poisonous—but unlike the other alcohols, humans can digest ethanol if given enough time and water. Though it will still kill you if you drink too much at once.
- Ethanol is the active ingredient inside our alcoholic drinks. While the other ingredients are there for flavour, the ethanol is there for the specific purpose of messing with your nervous system.
- When you drink alcohol, two processes kick off in a kind of race against time.
On defense: Your liver!
Since alcohol is toxic, your liver immediately starts trying to get rid of it. To process the alcohol, your liver and kidneys need lots of water, and they turn into giant sponges and suck the water out from everywhere in your body, including your brain (which is one reason why you get headaches, bad sleep and a hangover the next day).
On offense: The ethanol!
Unfortunately, your liver can only process ethanol at a certain speed. If you drink faster than your liver can burn it up, the excess ethanol runs into your bloodstream and starts knocking out all sorts of physical and mental control systems, and that’s when you start feeling drunk.
The universal physical and mental effects of alcohol
There are certain physical and mental effects of alcohol that everyone experiences the more they drink:
- Alcohol makes you feel sick—it upsets the balance of minerals in your blood and produces acid in your stomach that can make you vomit.
- It messes with your sense of balance and your fine motor skills, so you stumble, fall and get clumsy.
- It limits your focus and perception, so you can’t completely follow what is happening around you, and you have a hard time tracking what other people are saying or doing.
- It impairs your brain function, so you can only handle simple mental tasks.
- And last but not least, alcohol increases your sexual desire but reduces your sexual performance—which is a bit rude on the part of your own biochemistry.
Since none of these effects sound good, why does anyone drink alcohol at all?
The varied social, emotional and behavioural effects of alcohol
Many people say they like to drink because it helps them feel more relaxed and sociable.
But there’s something odd here.
The physical and mental effects of alcohol are the same all around the world: you can take anyone, keep giving them alcohol, and eventually they will experience the same physical and mental symptoms of sickness, dizziness, loss of coordination, foggy thinking, narrowed focus and so on.
In contrast, the social, emotional and behavioural effects are all different. Drunk people can be depressed, boisterous, angry, weepy, cuddly, quiet—all depending on the person, their culture, and their environment.
So what does alcohol do on this front?
Reduced impulse control
Alcohol makes it harder for you to do mental work, and since managing our own behaviour is a form of mental work, alcohol can make it harder for us to manage our own impulses.
This is important because people use alcohol to excuse or explain specific behaviours:
- “I groped you because I was drunk.”
- “I only got angry because I’ve had too much to drink.”
- “We got so drunk that we started running around the street with our pants down.”
But what’s important is that alcohol doesn’t make you do anything—it doesn’t make you want to touch someone, hurt someone, say something—it just makes it harder to manage impulses and stop yourself if you really want to do something.
The technical term for reduced impulse control is disinhibition (literally undoing your inhibitions).
While alcohol might not make you want to do anything specifically, it does potentially affect your behaviour another way.
Because alcohol reduces our overall mental capacity, drunk people can experience a kind of tunnel vision, which means they can be heavily influenced by standout details in their environment:
- If there’s loud music, drunk people will probably focus on that and start dancing.
- If there’s a conflict, drunk people might become intensely focused on it, and escalate to a full-blown fight.
- If a drunk person sees someone they find super attractive, they might become very fixated on them.
If you’ve ever been around anyone who’s drunk you’ve seen this kind of glassy stare—that’s drunken tunnel vision. The technical term is alcohol myopia (myopia means short-sightedness).
So one way to understand why drunk people do what they do, or to anticipate their behaviour, is to look around their immediate environment.
Anything really prominent—lights, noise, movement, colour, friends, notable strangers—will get their attention and they will focus on it, and potentially try to interact with it.
Social norms and expectations
Finally, we are heavily influenced by our own group norms and expectations around how people behave when they’re drunk:
- Some groups think being drunk means being excitable and happy.
- Some think being drunk means being rowdy or aggressive.
- Some think being drunk means being quiet and withdrawn.
- Some think being drunk means being more physically and sexually intimate.
No one of these attitudes is “true”: they’re just beliefs that over time have become social norms about alcohol.
This is especially dangerous in a social group whose alcohol norms are fundamentally disrespectful:
- “We use alcohol to get girls drunk so we can have sex with them.”
- “If we’re drunk, it’s fine to fight.”
- “If I’m drunk, it’s fine for me to touch someone or press up against them.”
These attitudes and behaviours are the result of individual choices - alcohol doesn’t cause anyone to be disrespectful of another, and alcohol cannot be used as an excuse to normalise disrespectful behaviour.
Alcohol in a nutshell
The essential key to understanding alcohol is that it is a depressant, meaning it slows our functioning and reduces our overall physical and mental capacity.
This is in contrast to drugs like amphetamines, which are stimulants. These drugs speed up communication between your brain and body, which can create a different kind of impulsive, over-excited behaviour.
You can make sense of everything we’ve said about alcohol using this lens. For instance, when people are getting excited and rowdy when drunk, the alcohol isn’t stimulating them; it’s helped them lower their own social and emotional inhibitions. And then if people keep drinking, the alcohol will reduce their mental and physical coordination to the point that they can’t stand up or hold a conversation.
If you’re really interested in some of the research into alcohol and why it affects us in the way it does, this page at the Australian Institute of Family Studies is a good place to start.