Conceptually the film is very much like Stanley Kubrick's "The Shinning". It deals with a parent going slowly insane and becoming a threat to the children. Both movies suggest a possibility of a supernatural explanation of the insanity. But the movies are made in such a smart way where there is enough doubt in those supernatural occurrences that you can read it as psychological deterioration only. Which is a very interesting challenge to a filmmaker. And young Spielberg pulled it off.