Catherine Zeta-Jones' representative said that she has checked herself into a healthcare facility to better manage her medication for bipolar disorder. The Oscar-winning actress is expected to complete a 30-day treatment program, reports TMZ.

In 2011, Zeta-Jones announced that she has bipolar disorder and was being treated by a mental-health facility in Connecticut. Since then, the 43-year-old actress has frequently expressed the wish to help remove any stigma attached to the illness and to also inspire others to seek proper treatment.

Zeta Jones "is committed to periodic care in order to manage her health in an optimum manner," said her representative.

The National Institute of Mental Health defines bipolar disorder, also known as manic-depressive illness, as a brain disorder that causes unusual shifts in mood, energy, activity levels, and the ability to carry out day-to-day tasks.

Individuals with bipolar disorder experience episodes of mania typically alternating with episodes of depression. Manic and depressive episodes typically last from a few days to several months and can be interspersed by periods of "normal" mood. Symptoms of bipolar disorder are different from the normal ups and downs experienced from time to time. Symptoms are severe; in fact, they can result in damaged relationships, poor job or school performance, and even suicide.

Properly treated, people with this illness can lead full and productive lives. Like diabetes or heart disease, though, bipolar disorder is a long-term illness that must be carefully managed throughout a person's life.

Most often, bipolar disorder develops in a person's late teens or early adult years. Half of all cases start before age 25, though some people have their first symptoms during childhood and others develop symptoms later in life.

Children with a parent or sibling who has bipolar disorder are four to six times more likely to develop the illness, compared with children who do not have a family history of bipolar disorder. However, most children with a family history of bipolar disorder will not develop the illness.

Because bipolar disorder tends to run in families, researchers are hoping to locate the genes that may increase a person's chance of developing the illness.