Can the mentally ill experience the dreams, visions, and voice of God? Can they still experience the gift of prophecy? I think so. Why not? Just because a person’s brain is temporarily sick, it doesn’t make the Holy Spirit, angels, and demons stop existing. Obviously a person who is sick like this, should be extra careful when it comes to Biblically evaluating such experiences, but I wouldn’t just write them all off. Here are some materials that have explored thought on the intersection of mental illness with the gift of prophecy…

Farges, Albert. Mystical Phenomena. Part II.I.6-8, II.II.3-6.

Heschel, Abraham. The Prophets. Part II, Chapter 12: “Prophecy and Psychosis.”

http://classic.studylight.org/con/ntb/view.cgi?number=T2517

http://classic.studylight.org/con/tcr/view.cgi?number=T2000

http://classic.studylight.org/dic/ebd/view.cgi?number=T2361

http://classic.studylight.org/dic/sbd/view.cgi?number=T2774

http://classic.studylight.org/enc/isb/view.cgi?number=T5660

http://classic.studylight.org/con/tcr/view.cgi?number=T1670

http://classic.studylight.org/dic/hbd/view.cgi?number=T1622

http://www.newadvent.org/cathen/11542b.htm