"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," her spokeswoman said Wednesday in a statement. "She's feeling great and looking forward to starting work this week on her two upcoming films."
Zeta-Jones, 41, was treated at Silver Hill Hospital, an 80-year-old nonprofit psychiatric facility in New Canaan, Conn., TMZ.com reported.
The actress spent about five days there, People magazine reported.
"Catherine has had to deal with Michael's illness and that's been hard," a friend told People, referring to husband Michael Douglas' successful battle with throat cancer. "She went in for a few days because she's about to start working on two movies."
They are "Playing the Field," in which she plays a newscaster who is one of three women vying for a soccer star turned kid's-league coach (Gerard Butler); and director Stephen Frears' "Lay the Favorite," playing the wife of a legendary gambler (Bruce Willis).
Bipolar disorder, also called manic-depressive illness, causes severe and unusual shifts in mood, energy, activity levels and the ability to carry out day-to-day tasks, according to the National Institute of Mental Health. There is no cure, and because it's a lifelong, recurrent illness, says NIMH, sufferers need long-term treatment to control symptoms. Bipolar II, the milder form, occurs in about 1 percent of the population.