The Welsh actress has revealed she got to know herself and her
68-year-old actor husband - with whom she shares daughter Carys, nine,
and son Dylan, 12, - much better since she was went public with her
diagnosis last year.
The 43-year-old 'Broken City' star told the December issue of InStyle magazine: "It's been an intense time, in good ways and bad. You find out who you really are and who you're married to. You find things inside yourself you never imagined were there."
Catherine also opened up about how she tries to keep herself healthy by completely avoiding the Internet.
She said: "You can't escape what people say, and if you're human it can be painful. The smartest thing I did was to stop going online. I'm the sort of person who will just look for the negative.
"My husband] Michael [Douglas] can't really understand it, but that is the way I am. With my bipolar thing, that's poison. So I just stopped. Cold turkey. And it's so liberating."
The actress is now hoping to remove the stigma attached to mental illness by going public with her diagnosis and help others in the same position.
She said: "I'm not the kind of person who likes to shout out my personal issues from the rooftops, but with my bipolar becoming public, I hope fellow suffers will know it is completely controllable.
"I hope I can help remove any stigma attached to it, and that those who didn't have it under control will seek help with all that is available to treat it."