Mental health practitioners have observed that in patients with a diagnosis of schizophrenia, often delusions exist that either exalt the status of the patient (eg, the patient is God's representative/messenger on earth) or denigrate the patient (eg, God or demons is sending messages to the patient specifying his/her sinfulness and need to be punished/purged/cleansed).
When people are raised on the Bible they learn that God or demons influence everything so they are inclined to believe that they are having a religious experience (good or bad) when these things are happening to them. But this belief could in fact be masking a person's mental health issues.
ALSO, deep, strong, intense meditation in an effort to draw close to God can in fact trigger psychosis - GOOGLE: "Meditation-induced psychosis".