This is not a major hollywood film, its a small time indy.
I doubt they are going to have a shrink on the set, its low budget (I'm referring to the indy note in the main story), its unlikely they will have a counselor or psychologist on the set (which does normally happen on larger productions when child actors are at work).
They did NOT use a body double. It said adults would have balked at these things. The kid didn't know any better. They are SO proud of themselves.
I recall an interview of the grown up Linda Blair recounting her experiences on the set of the Exorcist.
She didnt fully understand what was being filmed and said the director did a good job of shielding her in a way but while her voice was dubbed by Mercedes McCambridge for the final cut, the cast and crew were none-the-less very disturbed by this little girl speaking such vile dialogue and acting out certain scenes.
Bastard out of Carolina was a disturbing but well made movie as was Delores Claiborne that also dealt with a similar topic.