What is Bipolar Disorder?

There are two main types of bipolar illness: bipolar I and bipolar II. In bipolar I, the symptoms include at least one lifetime episode of mania—a period of unusually elevated or irritable mood—and usually episodes of depression. In bipolar II, people suffer from episodes of depression as well as episodes of hypomania, a mild form of mania where they have an elevated mood as well as high energy and activity levels.