10 Warning Signs of Bipolar Disorder: Depression and Mania Symptoms. Bipolar disorder is a mood disorder that is also known as manic-depressive disorder. This illness is a mood disorder which carries a psychiatric diagnosis. A person who is bipolar may experience deep depression with breaks of mania as a complete mood shift. There are considered to be five classifications of bipolar disorder. Bipolar 1 disorder is when a person experiences defined manic episodes.