People who suppress anger have an increased risk of becoming violent when drunk, a new study has suggested.
The research, based on a survey of nearly 3,000 young adults in Norway, found that drinking may inflict physical aggression among those who have a strong tendency to suppress feelings of anger when sober.
While previous studies have found a link between drinking and aggressive or violent actions, many of these were either performed in a laboratory or based on surveys from a single time period.
Studies carried out over a longer time provide a better clue as to whether drinking actually causes violence, or the behaviour is instead due to other factors, such as personality traits, LiveScience reported.
In the latest study, carried out by researchers at the Swedish Institute for Social Research, and the Norwegian Institute for Alcohol and Drug Research, the participants were assessed twice, first at 16-17 years of age and again at ages 21-22.
The subjects were asked how frequently they engaged in heavy drinking and in violent behaviours during the past 12 months. They were also gauged for their tendency to suppress anger.
The researchers found a 10-per cent increase in drinking to the point of intoxication and a 5-per cent rise in violence among the participants who reported a high inclination to suppress feelings of anger.
The researchers observed no such association among those who did not habitually suppress their angry feelings.
So those who held in their anger were more likely to get drunk and that drunkenness was linked to an increase in the likelihood of getting into a brawl, the researchers wrote in the latest issue of journal Addiction
"Only a tiny fraction of all drinking events involve violence. And whether intoxicated aggression is likely to occur seems to depend on the drinkers' propensity to withhold angry feelings when sober," they wrote.
They also said that those with pent-up rage might act violently, because drinking alcohol can result in loss of self-control.