Anecdotally, I've noticed that some of my most intense spiritual experiences have come during mood episodes, especially hypo/manic ones. Last summer I had a memorable one, in which I believed that several random coincidences were connected, and I was in the right place at the right time to handle them with the help of the Almighty. It was a mystical experience that in the light of reason seems sort of silly now, although I've always believed that God uses believers to advance His purposes in the world.

I told my pdoc about this awhile back, even though I was kind of embarrassed. He is a rare bird, however---a man of science, but also of faith---and he more or less said "OK, so how do you know it wasn't a mystical experience?" I guess that's a question that won't be answered until I reach the other side.