Alcohol and personality changes when drunk
It's a great evening. Lots of laughs, a few beers and then it all kicks off. A fight out of nowhere, over nothing. It's the angry drunk who gets punchy after having too much. It may not be physical violence. The angry drunk may just turn mean and verbally aggressive.
The angry drunk may be the most placid person in 'real' life but too much to drink seems to turn a switch in their mind.
Alcohol can seem to change people's personalities in other ways too. How about the timid work colleague who turns into the life and soul of the office Christmas party after they've knocked back a few wines.
Drink affects people in many ways. From the sad drunk who always ends up crying in the loo, to the mad drunk who does the most ridiculous and inappropriate things.
Angry when drunk
So why do negative emotions like getting angry or upset often go hand in hand with too much alcohol? It's a complicated conundrum with a number of possible explanations.
"One theory for aggression and depression is that alcohol narrows a person's focus so that they only attend to what's important to them at the time. That is, your mental focus is on events that support your feelings at the time," according to emeritus Professor, Dr Mary McMurran, clinical and forensic psychologist.
"So angry or aggressive people focus on threat signals. At the same time, alcohol diminishes the brain's problem-solving abilities and so, when intoxicated, people are less able to tackle problems rationally," adds Mary.
A study in the Journal of Experimental Psychology found that if you were a live-for-the-moment type of person you were more likely to be an aggressive drunk.
The study suggested that people who just focus on the here and now without thinking about the future are more aggressive than others when sober but are even more aggressive when drunk.
So being an angry drunk may be an extension of your sober personality. If you are quick to anger generally, that trait may be magnified through alcohol.
Why does alcohol make me angry?
"There is often an environmental component if the ambience is threatening. It may make you more aggressive or angry," explains Professor Jonathan Chick, chief medical advisor to the charity Drinkaware.
"However, it could be that alcohol is a depressant, and can depress parts of the brain that regulate emotions, and balance our reactions," he adds.
One reason for the mild-mannered person turning into an angry drunk is pent-up anger.
It may also be the case that you supress your anger in 'sober' life but after drinking it is released. One Swedish study found a link between people who hold in their anger and an increased likelihood of getting into drunken fights.
It also found that people who try to hold in their anger were more likely to drink to the point of being intoxicated.