Is Eleanor crazy? Or is everyone else crazy?

After watching movies like Inception and Shutter Island, our culture have been trained to assume that many events are not real, and they do take place inside of our head. This is the same with Eleanor. When we read her perspective of the stories, we can assume that this entire novel takes place inside of her head. Out of the four characters, we are only hearing about one person’s internal perspective, and that is Eleanor, therefore we assume that Eleanor is the main protagonist. So now that we understand Eleanor is  the main protagonist, the next thing we wonder is whether the events is a cause of the supernatural, or are these events in her head. The main event that causes much dissonance would be when Theo’s clothes get covered in red paint/ blood. This conflicts with one of the final scene when we find out that Theo exclaims herself that her clothes is fine. If this event is only happening in Eleanor’s head, then there are two possibilities.  Basically, Theo’s clothes were cover in Red, and that the residents of the house are facing possible realms of the supernatural, or Eleanor is mentally disturbed. We may even say that Eleanor could of possibly imagined that all of the events at the end as well, but this would be supported with limited evidence. Technically, every event that was supernatural may of been caused by another person. Luke could of written on the wall, Theo could of painted her clothes, Mrs Montague may of made every single thing up.