I don't think the problem is so much the guns as the culture of violence.

[Jackpine Radical]

53. The problem from a scientific perspective

really is that these cases are so rare (relatively speaking) that you don't have a large enough sample to extract meaningful information from.

It's a case of probably very diverse causes leading to similar tragic results.

What does Timothy McVeigh have in common with the Columbine kids, the Batman movie killer, or with Bundy? Are mass killers anything like serial killers?

Sometimes they are indeed psychotic, with long histories of mental illness.

Here's something from the Washington Post a few years ago. It's actually a pretty fair summary of the situation for a popular press story:

http://www.washingtonpost.com/wp-dyn/content/article/2007/04/16/AR2007041601831.html

Michael Welner, an associate professor of psychiatry at New York University, looking at it from the medical end, says, "There has never been a neuro-anatomical localization of mass shooting behavior."

Jack Levin, the director of the Brudnick Center on Violence and conflict at Northeastern University in Boston, author of more than two dozen books on murder and criminology: "We're still in the dark about where this comes from."

He co-wrote "Mass Murder: America's Growing Menace," in 1985. At the time, he recalls, "there was zero" research about mass killers, serial killers and the like -- the truly frightening icons of America's violent ways.

Since then there have been lots of books about serial killers, lots of brain research and many more mass shootings. There are MRIs and talk about high levels of neurotransmitters like dopamine and plunging levels of serotonin. There's research into the limbic system, a primitive part of the brain that controls emotions and behavior. New medications have revolutionized psychiatric care for depression, even psychotics.

None of it really touches the psychology of mass murder.

"In mass shootings, the killer is often killed themselves, so we don't really have the ability to interview and analyze them -- all you can really do is work off their behavior," says Neil S. Kaye, an assistant professor of psychiatry and human behavior at Thomas Jefferson University in Philadelphia. "The problem with that is that mass killers do this for multiple reasons, and even when you develop a profile of people at risk, 99 percent of them never go out and do anything bad."

Some of the research tells us the obvious: About 95 percent of mass killers are men, they tend to be loners, they feel alienated. They look normal on the outside and are really, really angry inside.