Bipolar II disorder is similar to bipolar I in that moods change between high and low, but in bipolar II, rather than experiencing mania, a person experiences hypomania, a less severe type of mania. Many people with bipolar II disorder also have depression. Symptoms of hypomania include rapid, loud speech, increased energy, decreased sleep, and rapidly changing ideas. This can lead to dangerous behavior. Treatments include lithium, antipsychotics, antidepressants, and more. Follow the links below to find WebMD's comprehensive coverage about how bipolar II disorder is caused, symptoms of hypomania, how to treat it, and much more.