Some children cope with loss better than others because of their temperament.
The children could be subjected to "secondary terrorism" -- a concept which emerged after 9/11 when people became psychologically scarred by rewatching everything on TV, he said.
"Children get anxiety just by watching everything about the shooting on TV," said Kazdin. "You don't want to paper over it as if nothing happened, but you don't want to keep replaying the scenes. ... Rituals and routines for children and adults relieve anxieties and are important."
Children who are not directly affected by the Tucson shootings can also be just as traumatized.
"All American children are touched by the tragedy," said Dr. Paula Rauch, director of the Marjorie Korff Parenting at a Challenging Time Program at Massachusetts General Hospital.
"Children have heard about this event from TV, from grown-ups talking - the death of a child is so evocative for all of us," she said.
"As adults, we have the ability to understand," said Rauch. "This event could have happened anywhere, but kids feel like it happened at their school."
She said parents should "check in" with their children and start a conversation in the "most general and open-ended way."
Ask children, "What are kids talking about at school? Is there anything you are worrying or wondering about?"
Or for a reticent child, "Have you heard the sad news from Arizona?" or "I heard it happened at a grocery store. You may be worried about mom going to the store."
Young children can naturally wonder if what happened to Christina-Taylor could happen to them.
"They may want to understand why people could do such a tragic thing," she said. "It's better to answer them at home and put it in perspective: 'That is very sad but there are more helpers than hurters in the world.' Focus on the idea that there are always lots of people wanting to do the right thing."
And tell children that these acts of violence are rare.
Attending the funeral can be a "life lesson" for children, as well, according to Rauch.
"Kids need to know why people have funerals and it's a coming together as a community when there is something sad," she said. "These are family values to share with a child."
ABC reporter Devin Dwyer contributed to this report.