Transcript for Mass Shootings and Mental Health
Did you know that he was sick? No, I thought he was a disillusioned, aloof, shy young man who needed as much love as we could give. He wasn't easy. He would suck the oxygen out of the room. The father of Adam Lanza now says there are times that he wishes his son had never been born. Do you ever feel that way? I -- that's a loaded question, Barbara. A part of me says yes. And, the reason is, because he did an awful lot of harm to young men and young women who didn't deserve to die. And my son did it. Peter Rodger, speaking to Barbara Walters about his son, Eliott, who went on a shooting rampage this spring in Santa Barbara. We're joined by Dr. Richard Besser and Andrew Solomon, author of the book "Far from the tree." Andrew, I want to begin with you. You have probably spent more time with the parents of these killers than anyone. Hundreds of hours with Dylan klebold's parents of columbine. For hours of peter Lanza, the father of the Newtown shooter. One thing shines through. Even if we resist it, we tend to blame these parents. You learn when you speak to them, they're victims, too. They are. We used to blame parents for everything. Autism, homosexuality. We have dropped that. We still blame parents when their kids commit crimes. While some kids have criminal tendencies exacerbated by abuse or neglect, there are many cases including all these of these in which an E essentially loving, atent I have family, has a child who incomprehensively has this terrible brokenness. I want to show more of this. Peter Rodger talked about missing those signs. You have said you're going to spend your life, and the reason you're doing this interview with me, to raise awareness for other families who live with children who are mentally ill. How can you do that? By telling Eliott's story. By looking at the red flags, the markers. The common traits between perpetrators. Asking families to understand, love, and support children who might be in the same position as Eliott. Rich, what are the markers? Yeah, you know, I think we would all sleep better if we could really predict who will be a mass killer. The thing he's talking about. Looking for someone who is isolated, a loner, disaffected, but that describes so many young adults. Adolescents. Even psychiatrists are no better than flipping a coin to determine who, with mental illness, is prone to violence. You spent so much time, Andrew, with parents who, in your book, "Far from the tree" have remarkable children with great talents and great disabilities. Is there any common threads that successful parents of these children share? If you're looking in the general sense. The parents who find some sort of meaning in having the challenge of having these children that are different do a better job of parenting them. Parents who believe they have meaning in their experience have children more successful than parent who is don't. You're looking at acts of crime like this, I don't think you can find the joy in it. All you can find are the pointers for how to perhaps prevent other events. You spoke to peter Lanza. Barbara spoke to peter Rodger. He came to the conclusion it would have been better had his son not been born. Sthat a different conclusion than Dylan klebold's participants reached. I spoke to sue klebold. She said, I wished I never had gone to Ohio state, I never met my husband, I never had this child, this horrible thing wouldn't have happened. Over time, I came to feel I love the children I had so much, I don't want to imagine a life without them. Even at the price of this pain. When I say that I, I'm talking about my own pain. Not the pain of other people. While I accept it would have been better for the world had Dylan never been born, I decided it would not have been better for me. She had to think about it so much. Rich, such a tricky area. The issue of mental illness and violence. We know people with mental illness are more prone to violence. But the overwhelming number of crimes are committed by people who are not mentally ill. If you look at overall gun violence, mental illness accounts for -- well, mass killings are less than 1%. Mental illness is about 4%. I view this as a public health problem. That's my background. If you do studies, you can understand the risk factors and how do you reduce that risk? The president asked for that after Newtown. When the congress didn't act, he's calling on research. This fall, the nih is conducting research to understand how much is related to mental illness, how much is related to gun policies. What things really work. If you do that, you won't eliminate the mass killings. Hopefully, you can reduce the chances these can occur. Let us hope. Up next, our "Sunday spot light" looks back at freedom
This transcript has been automatically generated and may not be 100% accurate.