I've recently come across this quote by Jim Carrey:

Depression is your body saying f*ck you, I don’t want to be this character anymore, I don’t want to hold up this avatar that you’ve created in the world. It’s too much for me. You should think of the word ‘depressed’ as ‘deep rest.’ Your body needs to be depressed. It needs deep rest from the character that you’ve been trying to play.