Bipolar disorder is a serious mental illness that is characterized by extreme changes in mood, from mania to depression. It can lead to risky behavior, damaged relationships and careers, and even suicidal tendencies if it's not treated.

Although bipolar disorder is more common in older teenagers and young adults, it can affect children as young as 6. Some experts believe the condition is rare and over-diagnosed; others disagree.

In general, women tend to experience more periods of depression than men, research shows. Women are also at higher risk for rapid cycling, which means having four or more mood episodes in one year.

Bipolar disorder and ADHD are being diagnosed more often in American children and teens. There are some similarities in symptoms, so how can a doctor know for sure if the child has bipolar disorder or ADHD?

Doctors don't completely understand the causes of bipolar disorder. Bipolar disorder often runs in families, and researchers believe there is a genetic component.

About 5.7 million U.S. adults are living with bipolar disorder. Bipolar disorder affects men and women equally, as well as all races, ethnic groups, and socioeconomic classes.

Although bipolar disorder cannot be prevented, early recognition of bipolar warning signs and seeing your doctor regularly can allow you to monitor your mood and medications and keep the illness from escalating.