Read this section on mood disorders. Mood disorders fall into the basic groups of elevated mood such as mania or hypomania, depressed mood of which the best-known and most researched is major depressive disorder (MDD) (commonly called clinical depression, unipolar depression, or major depression), and moods which cycle between mania and depression known as bipolar disorder (BD) (formerly known as manic depression). When reading this section think about the effects of mood disorders on people's lives. Major questions to consider include what are the major mood disorders? What are the diagnostic criteria? Who is affected by mood disorders?