People who were bullied at school will probably be able tell you how it affected them psychologically. But a new study published today suggests that childhood bullying could also lead to poorer physical health in adulthood - for both victims and perpetrators.

As well as psychological damage, research from the University of Warwick found that “involvement with bullying in any role was predictive of negative health, financial, behavioural, and social outcomes in adulthood”.

The study was based on 1420 participants who were assessed a number of times between the ages of nine and 26. The findings suggest that victims of bullying are significantly more likely to be diagnosed with a serious illness, smoke regularly or develop a psychiatric disorder.

Other negative outcomes include an inability to hold down a regular job, and poor social relationships.

Interestingly, those victims who then went on to bully others, so-called “bully-victims”, were the most affected. Bully-victims were more than six times more likely than those not involved to experience serious illnesses such as diabetes and asthma, psychiatric disorders such as depression and anxiety disorder, and to be regular smokers later on in life. They also tended to report more instances of poor health, and comment that they had trouble recovering.

Lucy Bowes, a Research Associate at the University of Bristol, who is interested in how being bullied might increase children’s risk of developing depression, said: “What is particularly unique about this study is the range of outcomes studied within the same dataset. There are relatively few studies that have been able to follow children into adulthood”.

Research into the effects of bullying started around 40 years ago in Norway. Since then, there has been increasing evidence that bullying is associated with psychological problems. However, it remained unclear whether bullying is a cause, or just an indicator of underlying psychiatric and familial problems, as bullying is more likely within certain groups that are also susceptible to health problems.

Dieter Wolke, who led the Warwick research, said that this study had factored in childhood psychiatric problems and family hardships. “This strongly indicates that being bullied is a precursor to developing psychological and health conditions, rather than a marker of problems,” he said.

Bowes cautioned that although the study adjusts for a number of childhood hardships and psychiatric problems, there may still be other factors that could explain the findings. “Certain inherited characteristics may increase children’s risk of being involved in bullying,” she explained. These characteristics could include a propensity towards aggression or anxiety, for example, that to some extent may arise from our genes.

“There is also a risk that children who are at risk of developing psychological or social difficulties may be more likely to perceive that they are being bullied,” Bowes added. But she agreed that “the growing body of literature suggests that being the victim of bullying is harmful in terms of psychological ill-health, whether or not that individual already had emotional problems”.

If bullying is not mostly caused by other background familial or psychiatric issues, then what causes it? This is what Wolke is keen to look into now. He recently began looking into other possible precursors of bullying, looking as far back as pregnancy. Early results show that those with mothers who were stressed during pregnancy are more likely to be victimised by their peers in childhood. Wolke wonders whether this programmes children into being more physiologically and psychologically reactive, and therefore more likely to be picked on by bullies.

Wolke and co-author William Copeland are now looking to study the biological mechanisms that may underpin bullying. “We periodically took blood from the participants of this study,” he said. “We want to see if there are biological markers that indicate children who bully, or are victimised, or both.”

This research parallels the work being done by Bowes’ team, which is currently investigating bullying in pairs of identical twins. “In situations where one twin has been bullied more than the other, it is possible to investigate physiological outcomes over time,” she said.

Wolke and team are also working on technological aids to combat bullying: a game-like programme of scenarios that children can use to find different strategies to deal with bullying.

“There are still some who think that bullying is part of normal growing up, a harmless rite of passage,” Wolke said. “Our research demonstrates how such an idea hides the pervasive and debilitating effects of bullying. We urgently need to get over this point of view.”