Aggression is defined as "any form of behaviour leading to the harm or injury of another person; the latter trying to avoid such treatment". Two questions regarding alcohol-related aggression are addressed: does a moderate dose of alcohol (resulting in a blood alcohol concentration <1.0 g/l - see alcohol content) increase aggression in human beings and, if so, under what conditions has such a relationship been demonstrated: what psychological mechanisms (theoretical models) can be used to understand this relationship?
Empirical results: Provocation and other factors in alcohol-related aggression. Alcohol consumed under non-provocative conditions does not increase direct physical aggression. In contrast, alcohol increases physical aggression if the subject is provoked. Alcohol in moderate doses favours aggression only in a situation where the subject, objectively or subjectively, has no choice other than an aggressive response. The type of drink has an influence on aggression: beer and wine elicit less aggression than spirits. This influence of type of drink is probably due to chemical differences between alcoholic drinks (congener content) or to the fact that people expect different effects from different beverages. Most studies have used male subjects and male targets of aggression. The few studies which have looked at female subjects have reported that reactions of women are no different from those of men. Reviews and meta-analyses have also revealed a strong relationship between alcohol intoxication and increased physical aggression.
A moderate dose of alcohol favours aggression, as long as the subject is provoked and has no choice other than an aggressive response. The "attention" hypothesis is the most convincing theory.
Alcohol and violence in adults and teenagers
Although alcohol abuse and alcoholism often appear to be associated with violence, this inter-relationship has not been clearly defined. It is a complex issue, due to the many factors (social, familial, genetic, biological, psycho-affective, etc) implicated in the expression of aggressive behaviour. For many authors, alcohol is involved in the transition to criminal behaviour.
According to different studies, alcohol seems to be a determining factor in certain types of criminal offence, which could be associated with lifting of inhibition, notably unpremeditated behaviour (sexual and physical violence). Alcoholic subjects more often commit assault and battery, murder and indecent assault. More than 70% of attacks and violent deaths were committed or experienced by people who were intoxicated, alcohol stimulating behaviour which is both aggressive and provocative. Although many studies highlight the association between alcohol abuse and antisocial behaviour in adolescents, the role of alcohol in juvenile delinquency remains unclear. A comparative study showed that a population of adolescents considered deviant (in a young offender's institution) comprised almost 79% alcohol abusers compared with 23% in a control population of adolescents in mainstream education. According to several studies, adolescents recognise alcohol as being a catalyst for certain types of violent behaviour, notably against another person.
