"A lot depends on whether the child is able to handle the script and to understand whether it's make-believe," said John Northman, a clinical psychologist in private practice, in Buffalo, N.Y. "It's important that a child not internalize the role by making that role part of himself."
Rudy Nydegger, a clinical psychologist with an expertise in child and adolescent psychology in Schenectady, N.Y., and professor of psychology and management at Union Graduate College, noted that on a film set the action is filmed in pieces, and the child actors tend to be professionals.
But damage could occur when non-professional child actors -- real kids -- make a movie on their own, he said. In the backyard, kids must create in that setting, often for longer stretches of time.
"They're not professionally trained to turn it on and off," he said. "The context is different. It's a lot more real in the backyard."
Lindsay Frame, an acting teacher at Anthony Meindl's Actor's Workshop in Hollywood, said, "Generally, by the age of 12, children who attend our school have a sense of their own boundaries when it comes to working with sexual content, swearing, or the like.
"Anthony and I have met the parents of our young students. And by the time the children start classes, they've already established a code of personal boundaries, with the help of the parent or parents, that they're comfortable with."
During classes, Frame checks in frequently with the children's comfort level, especially when students aged 12 or older are working with more adult-related content.
"If they're not comfortable, we allow them to sit out parts of the class," she said. "Open communication is very important."
Ultimately, it's the parents' responsibility to make sure what happens on a movie set has no deleterious effect on the child.
"The parent is accountable for finding out exactly what the part entails, asking the director how sensitive scenes will be shot, and letting the appropriate people know that a parent will be sitting in on the set," said McNeill. "Good directors are going to be looking out for these things, but parents should never make assumptions."