Schizophrenia before the age of about 19 is extraordinarily rare, and rarer still in girls. I'm shocked to hear of any such diagnosis for a 10 year old girl, especially if her caretaker was convinced she had it at 5. Adopted kids are sometimes troubled, and may have trouble adjusting to a new home, especially if they've been in what sounds like not a great home before that, but that is no reason to heavily medicate a child with anti-psychotics without exhausting all other options.