He's DEPRESSED because he's pathetic
and creepy and can't get girls.
The Big Bang Theory Season 2, Episode 12
Has he been DEPRESSED?
Breaking Bad Season 2, Episode 2
Well, not so much DEPRESSED
as lonely.
The Big Bang Theory Season 4, Episode 22
...green is jealous
and blue is DEPRESSED.
The Big Bang Theory Season 4, Episode 22
...because I'm fun,
I'm not clinically DEPRESSED at all.
The Big Bang Theory Season 6, Episode 5