Biology Of Violence

Is there any explanation for a massacre by teenagers like the one that occurred in Littleton? Psychiatrist Daniel Amen believes he has part of the answer. 48 Hours Correspondent Troy Roberts reports.

Dr. Amen thinks that violent teenagers have abnormal brains. Using 3-D computer imaging technology, Amen has spent nine years studying the relationship between brain abnormalities and behavior.

Dr. Amen, who runs a clinic in Fairfield, California, has done about 7,000 brain studies, which he says show that violent children have different brains than people who don't act violently. Amen has identified abnormalities in the left temporal lobe, which is the seat of aggressive thoughts.

Dr Amen has found a responsive audience among jurors, explaining in court the biological underpinnings of a defendant's violent behavior. He has testified as an expert witness for defendants in 20 criminal trials, including death penalty cases. In nearly every case, he says, his testimony helped sway the jury to be more lenient on the defendant.

Three years ago, Amen testified on behalf of 17-year old Joe Madrid, who was on trial for attempting to kill 16-year old Dylan Katz in Santa Rosa, California.

"I was dead," says Dylan. "I died a couple of times. But you know, people kept telling my parents to pull the plug, and neither of them would let them do that to me."

Madrid's attorney, Joe Stogner, hired Dr. Amen to testify that Madrid had no control over his violent behavior. Dr. Amen testified that Madrid had grown up in a violent household, and as a result didn't have the brain capacity to fight off the impulse to attack.

"His brain was very abnormal," says Dr. Amen. "In fact, his brain fit what we described as the classic pattern for violence. I testified to the fact that he had a violently vulnerable brain." Dr. Amen believes his testimony swayed the jury, which acquitted Madrid of attempted murder and convicted him on the lesser charge of aggravated assault.

Dylan believes that verdict was wrong: "They used my head as a trampoline. I'm sorry, but if that's not attempted murder, what is?"

Dr. Amen says his theory is not an excuse but an explanation: "I think it helps us in sentencing them. I think it helps in treating them."

Critics say Amen hasn't done enough research to pove his theory. But his work is about to be tested again in court. Amen says he's been hired by a young gunman--he won't say who--in a recent school shooting.

He says he is not, as his critics charge, eliminating personal responsibility: "If we ignore the problem and say 'no it doesn't exist'," he says, "it's going to wreak havoc."