No one will ever know what was going on in the mind of 20-year-old Adam Lanza, who police say was behind the elementary school massacre Friday in Connecticut.
Fernandina Beach child psychiatrist Carly Miller says the people who commit these types of atrocities are sometimes seen as outcasts, the victims of bullies, and socially awkward.
"I don't think anyone can say what's going on in that person's mind," Miller said. "Sometimes they're psychotic, they have sort of delusional ideas."
Miller said the emotional scars on the children who survived the rampage will likely last a lifetime, and they should all see counselors to avoid things like post-traumatic stress disorder.
"Anxiety, avoidance, later on, increases risk for drug and substance abuse," Miller said.
Miller said it's important parents across the country talk to their children about what happened in Connecticut. She said they should let them know that it's school shootings are rare and not likely to happen near them, but they should know about it.
"Absolutely, parents should talk to their children about it," Miller said. "I think the first thing they should do is listen to their children, let them describe how they're feeling about it, their emotions, their thoughts. And then kind of respond to what they say, answer their questions."
Outside Jacksonville schools Friday, many parents were worried.
"It concerns me because I have two kids going here, another down the street, and two more across town, so I'm real concerned as a parent about that," Patrick Lindsey Sr. said.
Lindsey said he's talked to his kids about safety, but this calls for even more.
"I will sit down and have a talk with them about it," he said.
Psychologist explains why mass shooters are often young men
A common theme among a series of mass shootings across the U.S. in 2012 has been the ages of the shooters, many of whom were in their teens or early 20s.
Dr. Stephen Bloomfield, a criminal psychologist in Jacksonville, says that could be for a number of reasons, including those in that age range who have feelings of self-importance and the fact that no one has detected a problem with them yet.
"Its almost impossible to prevent," Bloomfield said of mass killings.
Bloomfield said he has talked with murderers before, but not mass murderers. He said that's because most of them are either killed or commit suicide during the crime.
In recent history in cases like the one Friday at an elementary school in Newtown, Conn., the shooters are often young men.
"There is just more access," Bloomfield said. "First off, you can't rule out psychosis, and you can never rule out brain damage and things like that. And typically what happens as people get order and they have serious mental illness, it becomes identifiable."
With a young man, that mental disorder may not have emerged yet, Bloomfield said.
"We see young men for a number of reasons," he said. "I think we see them because of their impulsivity because of a sense of distorted narcissism, their own self-importance, which is normal at that age. But now it's magnified somehow."
Bloomfield said that's why there has been terrible crimes such as the movie theater shooting in Colorado, the mall shooting in Oregon, and now the elementary school shooting in Connecticut.
"One of the common themes in a murder like this is some type of revenge, that this was not random," Bloomfield said. "We know (the Conn. shooting) was not random. His mother was a teacher."