Most perpetrators of school massacres had struggled to cope with personal failure or significant losses, research shows. Many had attempted suicide or behaved in other ways that looked like a cry for help.
Yet failure and loss are universal experiences. There are many other potential factors - bullying, mental illness, exposure to violence, drugs, access to guns. Which of these account for the higher incidence of attacks in the richest country in the world?
After the Columbine shootings in 1999, when Eric Harris and Dylan Klebold killed 13, the US Secret Service and the US Department of Education established an inquiry that examined 37 similar shootings between 1974 and 2000. It concluded that shootings were rarely sudden - in most cases other people knew about the attacker's plans. Although there was no accurate "profile" of an attacker most behaved in ways that indicated they needed help. Many felt bullied or persecuted and there were often signs that they were planning for an attack.
In a recent article, Frank Ochberg, professor of psychiatry at Michigan State University said: "Students do not become mass killers overnight. They nurse their fantasies and they leak evidence. Insults, threats and plans are posted on websites. Classmates often know when a student is ready to strike back. Parents hear rumblings and have accurate gut sensations."
New programmes to share information led to several plots being nipped in the bud, he said. Other countries adopted similar programmes. Yet America is still the one where these tragedies happen most.
There is no evidence, Ochberg says, that, compared to other nations, the US has "more bullies, more bullying, more victimisation, and more victims who are ticking time bombs, hatching plots of lethal vengeance". Mental illness has been a feature, but people with mental illness are very rarely violent - they are more likely to be victims of violence. But occasionally they can become a danger to others.
"We do not have a sophisticated system of care and protection," Ochberg says. Community care for the mentally ill was "never fully funded" and "leaves much to be desired". But, he adds, the US in this regard is "really no worse than other nations".
Violence is ever present on TV screens and many commentators have suggested this can lead to copycat behaviour and desensitisation. Others counter that it acts as catharsis, defusing potential violent acts.
Ochberg notes that violent role models have a long history and are not limited to the US. "Northern Ireland, the Balkans, the children's armies of Africa, the terrorist camps of the Middle East, have their violent role models. Machismo is not an American word, nor is hooligan."
One factor is access to guns. If US students could not bring guns to school, we wouldn't have Columbine or Virginia Tech. "The reason we have an American school shooting problem ... has to do with access to loaded weapons by kids who should not have that access. Any serious attempt to prevent school shooting will have to attack the problem."
It is not a view likely to win wide support, especially in states with a powerful gun heritage.
After the massacre at Virginia Tech, Richard Arum, professor of sociology and education at New York University, challenged as to whether America's gun culture was to blame, was unapologetic: "Guns have been widely available in our society for a long time, and we didn't have this history of rampage school shootings."
But he agreed that when an individual with a history of mental illness was able to purchase a weapon, matters had got out of hand. "It would be hard to argue that this makes any rational sense at all."
- Independent
