I was thinking about it and I've come to the decision that Robin Williams wasn't a clinically depressed clown with mental issues, as he is being portrayed in the press.
According to the
nydailynews link on the previous page he had serious financial issues, which I take to mean that he owed a lot of money to wives/bank. He had recently stated that he had to put his home up for sale. They were coming after his assets and his only way out was to continue with his film making. When he tried doing his own original sitcom it was canceled after a short time by ABC. The big studios were only willing to pay him a paycheck if he played in the roles they wanted him in and returned to sequels promote their properties - ie. Night at the Museum 3 and Mrs. Doubtfire 2. The only problem is that Robin was a person who had great passion for his work and always said publicly that would only do a sequel if he felt it would be as good as or better than the original. In a recent late night interview when the host mentioned the Mrs. Doubtfire sequel the crowed cheered wildly and Robin Williams just gave a grim disappointed look and said it wasn't something he was looking forward to.
At the age of 63 he couldn't simply switch careers from something he had done all his life. He would have to compromise his artistic integrity to keep his head above water.
Having been married several times,
with all the cheating and lawsuits, he was clearly having companionship issues. According to that same link he spent very little time with his children as they grew up, always away doing his acting, probably more a figure coming in and out of their lives than a father. He named his daughter after a video game character, which she resented for a long time.
Robin William's finances were in shambles, his assets were being seized, his love life was non-existant, his relationship with his kids was negligible, his career was heading off a cliff, and he was being forced to make unwanted sequels and dress up as a woman for the entertainment of others. Unloved and at a dead end in life, I think that would be the end of the line for a lot of people.