Catherine Zeta-Jones is once more in treatment for her bipolar II disorder.

"Catherine has proactively checked into a health care facility," her rep, Cece Yorke, told PEOPLE, adding, "Previously Catherine has said that she is committed to periodic care in order to manage her health in an optimum manner."

Zeta-Jones sought treatment for the disorder, which has symptoms including high and low moods and bouts of severe depression, in 2011.

"This is a disorder that affects millions of people and I am one of them," the 'Rock of Ages' star said of her first treatment program. "If my revelation of having bipolar II has encouraged one person to seek help, then it is worth it. There is no need to suffer silently and there is no shame in seeking help."

A source close to the actress assures that there was no real trigger or issue for her return to treatment -- just that Mrs. Michael Douglas likes to keep her health in check and saw this as a good opportunity to do so before any trouble did arise.

"There was no big problem," the source confided. "This was just a good time to do it. She is in between projects. This has always been part of the plan. She would manage her health. She is vigilant about it."

Our best wishes to Zeta-Jones and her family as she continues to maintain her well-being.