Elijah was perhaps the greatest prophet of the Old Testament.
The author does not imply that Elijah was bipol.
His experience and subsequent reaction provide an interesting analogy of a bipolar episode.
Chapter 6 deals at length with the experience of Elijah the prophet and his experience on Mount Carmel as he faces the prophets of Baal.
And yet the book of James tells us he was still a man with weaknesses, not so different from many of us today.
The Hebrew people revered him as such.
Elijah was perhaps the greatest prophet of the Old Testament