There are many roads into bullying, from jealousy to observing the bullying of others and copying it to make sure it doesn't happen to you. But studies agree that one of the important risk factors is being a victim. A recent study suggests that one in six bullies is a victim1; earlier, larger studies have suggested the figure is more like half2, 3.
That large youth terrorising a stammering, uncoordinated boy in the school toilets may also have been abused by his own tormentor - and perhaps still is. And the head of department who is making your life hell may have had a nightmare-ish time as a newly qualified teacher.
This large group of so-called "bully victims" is worth special attention because the evidence shows they are both more physically aggressive and more troubled than other bullies. They are more likely to be depressed and anxious, have poorer peer relations and behave worse in school. And they need help just as much as their victims because, behind that facade, they are still victims themselves.
What goes on inside the mind of a victim that brings about this transformation? When somebody experiences significant bullying, especially in childhood, it can alter their personality. They become hypersensitive, and may constantly scan their environment for any signs of bullying. In this hyper-vigilant mode, people can frequently misjudge social and emotional situations. The "victims" want to protect themselves and others, but frequently become over-defensive - which can lead to offensive behaviour.
This is a complex process, but there appear to be two main streams of thought underlying it. The first is: "I will never be a victim again." The victim overreacts to any situation where they feel they might be bullied and makes pre-emptive strikes to avoid it. The second is over-identification or empathy with other victims. What starts as protection for fellow victims can become vigilante-like behaviour accompanied by excessive aggression.
The problem with both modes of thinking is that the "victim" feels justified in their actions, which they carry out with the passion of the righteous, so they can lack insight and natural self control.
In addition, they can often identify with the bully. This is partly pure self-defence - you need to know your enemy - but is also driven in part by the satisfaction of being the one in a powerful position. Ultimately, the safest position (as seen by a distressed victim) is that of the bully.
These psychological processes may explain why "bully victims" tend to be more troubled and violent. But it seems there may be long-term physical effects of bullying too.
Levels of cortisol - a stress hormone - are raised in the brains of frightened victims. "Children who are bathing their brains in cortisol may be at risk of abnormal brain development and irreversible changes to the brain," says Dr George Holden of the University of Texas in Austin. These changes can have long-term effects on the immune system and on cognitive performance.
Other changes found in a separate study by Dr Yvon Delville6 suggest a physical trigger that could turn victim to bully. He has demonstrated that, as with hamsters, humans seem to retain a tendency to become aggressive faster if they were bullied as teenagers. This is likely to be because - as with the hamsters - they have experienced chemical changes in the brain, involving serotonin, dopamine and vasopressin levels.
The outlook for many bullies seems to be poor. A longitudinal Norwegian study showed bullies were three or four times more likely than their peers to have multiple convictions by their early twenties7. Some 60 per cent of the boys identified as bullies in middle school had at least one conviction by the age of 24, and 35 to 40 per cent had three or more.
What can schools do about this? They should create an open, trusting atmosphere in school and nip any bullying in the bud, paying just as much attention to bully as to victim.
Dr Sandra Scott is a forensic psychiatrist at the South London and Maudsley hospitals trust and adviser to television shows including I'm a Celebrity and Hell's Kitchen.
1. Harriet A. Ball, Louise Arseneault et al, Genetic and Environmental Influences on Victims, Bullies and Bully-victims in Childhood, Journal of Child Psychology and Psychiatry (2008) 49:1, 104-112
2. Denise L. Haynie et al, Bullies, Victims and BullyVictims: Distinct groups of at-risk youth, The Journal of Early Adolescence (2001) 21:1, 29-49
3. Roberto Forero et al, Bullying Behaviour and Psychosocial Health among School Students in New South Wales, Australia, British Medical Journal (1999) 319:7206, 344-348
4. D. Schwartz, Subtypes of Victims and Aggressors in Children's Peer Groups, Journal of Abnormal Child Psychology (2000) 28:2, 181-192
5. Louise Arseneault et al, Bullying Victimization Uniquely Contributes to Adjustment Problems in Young Children: A nationally representative cohort study, Pediatrics (2006) 118, 130-138
6. Yvon Delville et al, Behavioral and Neurobiological Consequences of Social Subjugation during Puberty in Golden Hamsters, The Journal of Neuroscience (1998) 18:7, 2667-2672
7. Norwegian study: Dan Olweus, Bullying at School: What we know and what we can do (Blackwell, 1993).