EWTN Catholic Q&A
Question from Anonymous on 10-10-2013:

How can you tell if someone is really experiencing mysticism or revelations and is not undergoing some sort of psychological disorders?

Answer by Richard Geraghty on 10-16-2013:

Dear Anon,

lIt is very hard to tell. But one sign of authentic mysticism is that the mystic is obedient to the Church and that the revelations are in accord with the Church. This does not mean that mystics cannot rock the boat. Pope Francis is doing a good job of that right now. Yet he is very orthodox, as one might expect a Pope to be.

Dr. Geraghty