You've touched a moot point Christian about the high frequency of comedians and funny people who suffer depression or attempt suicide as well.
Besides Robin Williams, other names that come to mind are Tony Hancock, Dick Emery, Bert Newton, Eric Sykes, and others if my memory serves me correctly. I think I recall Robert Culp forcing Bill Cosby to speak up about his moods too (in an interview).
Seeking out professional help may be a first step; but it's a big step. And one might not have to look back. So I concur.