Why alcohol makes some people violent

Heavier drinkers are much more likely to be involved in violence if they have suffered high levels of adverse childhood experiences (ACEs), according to a new study.

The link between ACEs, alcohol and violence is especially pronounced in young men (18-29 years), with 62 percent of those with high levels of ACEs who are heavier drinkers having hit someone in the previous 12 months. This compares to 13.5 percent in heavier drinkers with no ACEs.

The study by Public Health Wales and Bangor University of 12,669 adults across England and Wales is published today in the medical journal, BMJ Open. The results show:

• 1.3 percent of men with no ACEs who were moderate drinkers or abstainers had hit someone in the last 12 months. This rose to 3.6 percent in those with no ACEs who were heavier drinkers. However, levels escalated to 28.3 percent in those with who were both heavier drinkers and had experienced high levels of ACEs (four or more ACE types) as a child
• The combination of ACEs and heavier drinking increased risks of recent violence in individuals of all ages studied (up to age 69). However, the effect was particularly marked in young men aged 18-29, with more than six in 10 (62 percent) of those who were heavier drinkers and had high levels of ACEs having hit someone in the last 12 months
• The equivalent figure for women was lower but still substantial. Approximately one in four (24.1 percent) women aged 18-29 who were heavier drinkers and had high levels of ACEs had hit someone in the last 12 months
• Overall, 8.6 percent of men in this national sample reported high levels of ACEs in their past and over half of those with high ACEs also reported heavier drinking levels. As a result, one in 20 of all men studied reported the most violent combination of a history of high ACEs and heavier alcohol consumption

Lead author of the study, Professor Mark Bellis, Director of Policy, Research and International Development at Public Health Wales, and Honorary Professor at the College of Human Sciences said:

"We know that people who suffer high levels of adversity in their childhood can find it more difficult to control their emotions as adults, including feelings of aggression. Our results suggest that when they are also heavier drinkers this may further erode their control and increase the risk of them being involved in violence.

"Unfortunately, our results also suggest that individuals who were abused and neglected as children or exposed to traumas such as parents fighting in their home are also more likely to become heavier drinkers. In many circumstances drinking more heavily may be something they began in order to cope with childhood traumas.

"Sadly, a toxic mix of childhood trauma and high adult alcohol consumption is not uncommon, and we found this combination in one in 20 of all men we surveyed. Such individuals are more than 20 times more likely to have hit someone in the last 12 months compared to lower level drinkers with adversity free childhoods."

Other results from the study identified similar relationships between ACEs, alcohol use and being a recent victim of violence.

• In women with no history of ACEs who were moderate drinkers or abstainers, less than one percent (0.8 percent) had been hit in the last 12 months but this rose to 13 percent in those with high levels of ACEs and heavier alcohol consumption
• In men this difference was even more marked rising from 1.9 percent (no ACEs and low or no alcohol consumption) to 32 percent (high levels of ACEs and heavier alcohol consumption)

Professor Karen Hughes, co-author the study, also from the College of Human Sciences, said: "If you hit someone you are more likely be hit yourself and this may be part of the explanation why people who are currently heavier drinkers and have a history of adverse childhood experiences are more likely to have been a recent victim of violence."

"However, for some people their childhood adversities will have included experiencing violence and seeing domestic violence in their homes. Some women who experience such childhoods may believe suffering domestic violence is expected and so stay in abusive relationships and use alcohol as a coping mechanism."

The paper concludes that results support wisdom established for over two thousand years such as in vino veritas (in truth wine) which suggests that alcohol can expose underlying traits that people may otherwise wish to supress.

The study combined data from four studies undertaken in England and Wales between 2012 and 2015.