Possible novel inspiration?
I remember reading a book as a kid (i.e. in the 1990s, early 2000s) that had a similar beginning premise. There was a girl and a Russian (?) boy who had identical brainwave patterns, and ever since they were very small they "shared" minds. One would pass out inexplicably and find himself/herself in the other kid's mind, and could see what they saw, feel what they felt, etc. But instead of being a romance novel, the boy is somehow put in danger, and the girl has to use their mind-connect to find him and save him.
I thought the book might be some uncredited inspiration for the director. Does this ring any bells?