A recent comment of mine:

In an old interview, Mr. Narcissus [Elon Musk] said he may have bipolar disorder; he said he experiences "great highs, terrible lows, and unrelenting stress".

He has doubts because his highs and lows follow events in his life, whereas episodes from bipolar disorder often appear without triggers. [...]

We'd know if he went for an evaluation/possible diagnosis, but I cannot even imagine him doing it.

Kanye West is usually manic when he acts this way. I guess this supports Musk's suspicion.