Bipolar disorder. They are referred to as disorders. If you google disorder vs disease you will find that some dictionaries distinguish between the terms, with disease indicating something caused by a virus or bacteria and disorder having to do with congenital or mental illness. Some, however, make no distinction and the words have essentially become synonymous in common parlance as well as in the mrdical literature.
Bipolar. Bipolar disorder is a condition in which an individual experiences marked highs and lows in their energy level and mood. Depression and bipolar disorders are both considered mood disorders. Depression is what occurs at the low end of a bipolar disorder, when the person is not feeling activated. A unipolar depression on the other hand, does not require the person to have up periods. An older name for bipolar disorder is manic depressive disorder. I hope this is helpful.