Before the shootings occurred I had been looking into research regarding school shooters, only to find that there is a paucity of information about them and what makes them tick. Perhaps the only thing we can say with assurance is that they are male. Otherwise, common characteristics frequently appear in lists that are frustratingly general in nature and questionable in their utility. The Federal Bureau of Investigation (1999), for example, provides no fewer than 28 characteristics of a possible school shooter, enough to confuse almost anyone trying to determine if a student may be a real threat to others. As PBS's Frontline puts it,
A review of the [available literature] shows loose consensus around a number of warning signs for potential youth/school violence: chronic feelings of isolation or rejection, frequent angry outbursts, social withdrawal or depression, fascination with or possession of weapons, alcohol or drug dependency, history of bullying behavior, and lack of interest in school or poor school performance. Then there are items common to several lists, but not to all, like cruelty to animals and gang affiliation. And then there are some items that appear only on one or another list -- "dresses sloppily," is a "geek or nerd"; "characteristically resorts to name calling, cursing, or abusive language" -- that seem to be only marginally useful as warning signs . . . .
The lack of understanding regarding school shooters seems due to the fact that information about shooters is collected after the shooter or shooters are dead and the victims have been buried. Then, it is typically the press that investigates the shooters, their early lives and parenting, friendships or lack of same, all with an eye to selling papers or presenting a story on the evening news. "Psychological autopsies" are conducted by well-meaning researchers and writers of various stripe. The water gets muddier and muddier.
Perhaps the biggest obstacle to our understanding of school shooters like Lanza is that we have little or no basis to compare them psychologically with other students. We need to conduct comparative, psychological studies of students over time to determine how -- and why -- some turn out to become violent while others do not. It is only through such longitudinal research grounded in potent psychological variables that we may finally determine ways we can prevent shooters from killing. Although it is true many shooters reveal their plans to others before they murder, such information may not be taken seriously or reported to people who will take appropriate precautions.
In Lanza's case there was little or no warning. His mother was thoughtlessly stoking his violent fantasies by providing him with firearms and ignoring the fact that her son was increasingly withdrawing from society. One wonders if Lanza had any relationship with his father, and how mother and son related to one another. I suppose as time goes on we will know more, but in the end there will likely be more questions than answers.