It's not a fair question, says Edward Taylor, a professor of social work at the University of Illinois. As a researcher of mental illness in children, and author of a recent article on the topic for the journal Child Welfare, Taylor notes that even highly trained mental health professionals would have had little chance of predicting those kids would commit that kind of violence.

"We simply don't have the tools to do that," Taylor said. "We still do not understand human development to a point of predicting violence. We can retrospectively look back and say 'Gee, this was a sign, that was a sign,' but it wasn't necessarily a sign."

"There were things going on in each of the cases that seem to indicate that these children, if looked at closely, would be in a higher probability of needing help with a mental health issue. But they were not flags that said 'out of all the kids, this kid is going to go and become an assassin.' "

Taylor, who is developing a proposal for a long-term study to identify predictors of violence in children, said he is concerned that school shootings will reinforce widespread misconceptions about links between mental illness and violence. Mental illness may have played a role in the various shootings, he said, but the vast majority of people with mental illness are not a danger to others. Reinforcing the perception that the two are linked can only increase the stigma that keeps people from seeking treatment, he said.

Only a small percentage of kids are going to have major mental health problems, Taylor noted, and only a very small percentage of those are likely to become violent. Adding to the difficulty in identifying and treating those few is that certain symptoms or tendencies that might indicate a mental health problem are even more likely to indicate only a learning disability -- which teachers are much more likely to be looking for.

Taylor said he's also concerned that schools and communities can overreact to the recent highly publicized incidents, and, in the process, hurt a lot of children.

Although schools could do more to identify students with mental health problems, they know that most kids' problems are situational and temporary, he said. "Schools are dealing every day with hundreds and hundreds of kids that go through hundreds and hundreds of situational crises -- and out of those hundreds and hundreds of situational crises, there's going to be a small number of people who are severely mentally ill who are going to get missed.

"But we certainly don't want a school system that every time a child throws a temper tantrum, every time a child says something aggressively, that they are immediately suspect of becoming mentally ill and violent."

Note: If no author is given, the source is cited instead.