I havent seen the movie yet but read the book many times. I didnt take the book as an example of a dissociative event. the boy wasnt under extreme abuse, he wasnt experiencing numbness or feeling like he wasnt real and wasnt feeling like things in his room werent real and he wasnt switching into alternate personalities. in the book it started with he was told to go to his room without dinner because he was mouthing off to his parent. the parent wasnt hitting him, beating on him, the parent wasnt sexually assaulting him or anythnig. he was just told to go to his room for mouthing off. then in his room he pretended he sailed across the sea not floating outside himself not floating and far away from himself. he pretended he had animal friends in far way lands. as far as I know dissociation doesnt include having imaginary friends. then when he smelled food and felt hungry he pretended he was sailing back over the sea leaving his imaginary friends and there in his room was his dinner where his parent had left it. I know that dissociation includes things like feeling numb not feeling things like feeling hungry and smelling dinner, one dissociative disorder specifically states there cant be imaginary friends. So I never took the book to be about a boy dissociating, or a boy having any dissociative disorders. maybe the movie does more speculating and ading things that the book never had nor meant it to be. I dont know but its a far reach for me to see it as a dissociative event if its like the book.