The death of Robin Williams makes me think of all of my friends whose lives have been scarred by a suicide, and all of my friends and family who - like me - struggle with the devastation of bipolar disorder and depression. We always wonder what we could have done for each other, when one falls - whether we could have changed the trajectory, somehow.
All we can do is all we can do. Listen, when people are in pain, and take them seriously. Really listen. It's the most important thing.