If true, what an embarrassing way to go. Sometime I wonder WTF is wrong with some people. What a waste.
I strongly suspect that Robin Williams had a severe case of manic depression, either undiagnosed or untreated. It is extremely exhausting to its victims, who often meet untimely ends.
In their manic phase, they are often very entertaining, with a sharp wit and surprising spontaneity. One doctor who worked at a psychiatric hospital had a manic depressive patient, and he described an encounter.
He was holding a conversation at one end of a long and crowded corridor, when a female patient with m-d saw him from the other side of the corridor. She shouted his name, “Mark!”, to attract his attention, then repeated herself again and again as she walked towards him: “Mark! Mark! Mark!”. He pretended to ignore her rudeness.
Finally when she arrived where he was standing, she paused for a moment, then said, “Gee, I sound like a dog with a hairlip!”