It was later "confirmed" by shelleycat, who said her mom used to know him a couple decades ago when she used to work for/with him on something or other and that she herself had met him once or twice because of that. Although shelleycat brought this up during out last year together, a point at which her own mental illness made it impossible to rely 100% on anything she said, so who knows.
But in any case it seems that a large number of people either didn't know he was bipolar, or somehow never made the connection that being bipolar (usually) involves periods of depression.
I've never really liked Robin Williams' humor much. Looking through his filmography the only things he's been in that i've really liked have been Dead Poets Society (and i'm wondering a bit how Robin Williams' suicide will affect future interpretations of that movie,) Aladdin, and The Birdcage.
But despite that i obviously still feel sad for him as a person and for his family for what they're going through. Even though if he weren't famous most of us wouldn't have ever heard about his death. And his struggle with mental issues and subsequent death, combined with shelleycat's story about him, makes me think about her. Especially since after she died i did find a suicide note from her that she had written months earlier, although the (physical) medical issues that made her think suicide might be a reasonable option killed her before she ever decided to follow through on it.