BBC Radio 4 is doing a series of shows called U.S. Comics Confidential that profile/interview great American comedians more in the area of serious biography than entertainment. I think this link will allow you to listen to an excellent 30-minute broadcast about Jonathan Winters discussing, among other things, his bi-polar disposition. The link may not work forever so don't delay. The next broadcast, which is June 28, will be about Phyllis Diller and I'll try to link to that once it's online.