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You probably know how it will end when you and your crew decide to go shot-for-shot — all of the same poison, and things get a bit out of hand.

An hour later, one of you is squaring up to fight a coat rack. Another is crying uncontrollably and confessing feelings of inadequacy. The third is giddily putting the whole thing on their Instagram story. Uh… what’s going on here?

Research on the effects of alcohol yields some clues: It may be possible to predict how people will behave when they’re drunk, way before the bar fight breaks out, by observing how they behave sober.

Alcohol is a disinhibitor, meaning it suppresses inhibitions in our brain, leaving us feeling more impulsive, less anxious, and less restricted — and sometimes, if the drink special is good enough, flat broke.

“Alcohol tends to amplify certain personality traits — such as aggression, amicability, etc. — but it won’t typically create a 180 degree change,” said Jason Edmonds, a pharmaceutical biologist.

“For example, a person who habitually becomes aggressive when intoxicated likely has tendencies toward aggression and frustration when sober as well,” says Edmonds.

Research suggests alcohol affects people’s behavior in different ways, but much of it depends on their personality. According to recent research on alcohol’s influence on behavior, people tend to believe alcohol changes their personality more than others around them.Winograd RP, et al. (2017). An experimental investigation of drunk personality using self and observer reports. DOI: 10.1177/2167702616689780

In other words, the old saying, “A drunk man’s words are a sober man’s thoughts,” might actually have some accuracy to it. But the way you act while drunk is about more than just what you feel inside.

“Although we’d like to think that there’s a single explanation out there for what predicts if you are a ‘happy’ or ‘sad’ drunk before the night begins, that may not be the case,” said Jessica Magidson, PhD, psychology professor at the University of Maryland.

Below are examples of common types of drunk behavior and their potential causes:

People — especially men — who are prone to anger or aggression while sober are more likely to act aggressive when they’re drunk. Shocker, we know.

Researchers describe these folks as impulsive and short-sighted. But there’s also evidence that alcohol inhibits our ability to detect fear and sadness in others. That may be why you’re totally oblivious when you drunkenly run into someone walking across the club.Honan CA, et al. (2018). Alcohol intoxication impairs recognition of fear and sadness in others and metacognitive awareness of emotion recognition ability. DOI: 10.1037/emo0000404

Those who keep it cool regularly often stay that way when drinking, even after someone provokes them. People who are forward-thinking and consider the consequences of their actions when sober are less likely to get out of hand when they drink. (“He’s a jerk, walk away…”)

But while the calm drunk may get Zen-like in the moment, research shows that alcohol’s relaxing effects are short-lived. The Anxiety and Depression Association of America reports that about 20 percent of people with social anxiety disorder also have issues with alcohol abuse or dependence.

And while that first post-work margarita may feel relaxing in the moment, alcohol can elevate anxiety levels hours later — sometimes even into the next day.

When stressed, people sometimes drink to unwind. (“A toast to this job we hate!”) But medical research is increasingly finding that excessive consumption of alcohol over the long term can actually cause stress by changing the brain’s neural pathways.Becker HC, (2017). Influence of stress associated with chronic alcohol exposure on drinking. DOI: 10.1016/j.neuropharm.2017.04.028

So next time the boss offers to buy, consider declining.

In addition to personality traits, physiological traits can also influence drunk behavior. Research suggests that about 0.05 BAC is the level where people reach maximum giddiness. Beyond that, you’re just impairing judgment with alcohol so you think you’re feeling more euphoria.

And the more you drink, the longer it takes you to get to the same level of intoxication. That’s one reason hard drinkers may be more likely to be associated with this kind of drunken demeanor — but as mentioned, it depends more on what the person is like while sober.

“Take me drunk, I’m home!” Unlike heavy drinkers, people who rarely have more than a sip of Chardonnay tend to feel sedate when they drink. Prepare to be carrying these folks into a cab after a night out.

A landmark 2001 review on alcohol’s impact on sleep showed that alcohol consumption 30 to 60 minutes before bedtime was positively correlated with increased sleepiness, but may also cause restlessness and poor quality sleep during the second half of a sleep session.Roehr T, et al. (2001.) Sleep, sleepiness and alcohol use.

The characteristics that come out after a few rounds at the bar may be hidden at work or other social situations, since alcohol can make people act without worrying about consequences.

“They might be able to better control these emotions when sober, but they’re still present on some level,” said Edmonds.

That’s why heavy drinking around coworkers is nearly always a bad idea. One minute you and Karen from accounting are exchanging polite jokes over daquiris. The next, she’s running out of the bar in tears because you told her what you really think of her gerbil desk calendar.

“The individual brings some things to the equation,” says Magidson, “but the reality is that this ‘mixes’ with the environment one is drinking in.”

Luckily, there are ways to avoid getting into a fight or ruining relationships with coworkers because of a happy hour that got a bit out of control. Here are a few tips:

1. Be in good company

Steer clear of situations and people that trouble you when sober. If your girlfriend’s one friend has you rolling your eyes during appetizers, don’t go shot-for-shot with them after dessert. It’s not going to end well.

2. Know how much is too much

According to the NIH, “heavy drinking” generally means more than four drinks per day for men and more than three for women. But you should also understand your own personal limits and when you should stop.

If you often lose track of the number of drinks you have, consider counting them using a smartphone app or similar method. Make sure the count will be somewhere you can see it.

3. Hydrate

Alcohol is a diuretic, meaning it makes you urinate more frequently. This can cause dehydration. Stay hydrated by making sure you drink one glass of water for each drink, or choosing mixers like water or club soda.

Remember, as much as we’d like to think we know what will happen when we drink, alcohol can affect our brains in surprising ways.

“What often predicts how we’ll act when drunk is a combination of numerous factors, many of which we probably don’t have control over,” said Magidson.

So, if you want to guarantee you don’t wake up the night after a bender with a pounding skull and a guilty conscience, there’s only one method guaranteed to work: don’t get drunk in the first place.