Catherine Zeta-Jones treated for bipolar disorder

(CBS) Actress Catherine Zeta-Jones sought treatment for bipolar disorder after dealing with the stress of husband Michael Douglas' battle with throat cancer, her rep said Wednesday.

"After dealing with the stress of the past year, Catherine made the decision to check in to a mental health facility for a brief stay to treat her Bipolar II disorder," the rep said in a statement. "She's feeling great and looking forward to starting work this week on her two upcoming films."

Pictures: Catherine Zeta-Jones
Pictures: Michael Douglas

It was not disclosed where or when she sought the treatment. A friend told People magazine that the Oscar-winner spent about five days in the facility.

"There's no question it's been a stressful year," the friend added. "Catherine has had deal with Michael's illness and that's been hard. She went in for a few days because she's about to start working, and wanted to make sure she's in top form, which she is."

Bipolar disorder is a mental illness marked by alternating periods of elevated or irritable moods and depression. According to the National Institute of Mental Health, those who suffer from "Bipolar II" tend to have longer periods of depression and do not have full-blown "manic" episodes.

Douglas, 66, underwent chemotherapy for stage four throat cancer last year and announced in January that his tumor was gone.