I think the Propher Mohammed was bipolar.

The suras of the Koran are like poems, he experienced terror when the Koranic voice first came to him and believed he was being spoken to by the angel Gabriel.  He also tried to resist it but could not (his wife Khadija was of great comfort to him).  He was also tempted to commit suicide because of the anguish and terror of the experience.
As a Turkish psychiatrist once told me:  bipolar disorder is good for society but bad for the person who has it.

The Prophet Mohammed:  Peace be Upon him.