Depression isn't just being a bit sad. It's feeling nothing. It's not wanting to be alive anymore.

“Yeah, Quirrell was a great teacher. There was just that minor drawback of him h…”

“Oh, most think he's barking, the potty wee lad, but some are more kindly and th…”

“Why are they all staring?" demanded Albus as he and Rose craned around to look …”

“This is night, Diddykins. That's what we call it when it goes all dark like thi…”