Apparitions from heaven???

[abaris]

Also, the boy stayed in the hospital for some time and was also treated by doctors and psychologists. Does that count?

Since the film is from the early 70ies and based on a book that - naturally - was written even earlier, not really. The real breakthrough in psychology or psychiatry happened at a later point in time. Much later, actually. There are mental conditions the people in the 60ies and 70ies didn't know the first thing about.