He says he takes it as prescribed against occasional depression.
No one should trust a thing he says after his baseless libel against the rescue divers in Thailand. ABSOLUTELY no one trust should anything he says after the "funding secured" BS, and if you got that far, saw the obvious lies and fakes he posted to Twitter even before he bought the place, I don't know what else to tell you.
At this point it's safer to assume that if Musk says something it's wrong.