Isn't doubting if Catherine Zeta Jones diagnosis similar to someone telling you , "Are you sure you're really sick? Isn't it just stress. You just need to relax!"

We don't know the full story, she may have had symptoms for years that she was either able to manage or deal with until her life got really stressful.

The only thing in the news I can find about Michael Douglas "blaming" his wife for his cancer was saying it was from HPV from oral sex but not specifying who gave him HPV. I don't know how long it takes for HPV to cause cancer in the throat, but in cervical cancer it can take something like 10-15 years before the pre cancerous lesions turn cancerous, but sometimes it can take longer. And in throat cancer it can increase the risk, not just cause it.

But there's nothing that I've read where he's blaming her bipolar disorder.

It's hard to say who was the first movie star or celebrity to be the first to talk about it. Until the studio system was broken Hollywood studios had strict control over directors,actors and actresses in their systems and not just over what projects they could and couldn't do but also their personal image.