Mood may be elevated, normal or depressed. When depression impacts daily life in a negative way, it may be diagnosed as a (or component of a) mood disorder.
Depression is a feature of bipolar and cyclothymic disorder. People with bipolar disorder suffer mood swings from depressed to manic (a high level of elevated mood).
People with cyclothymic disorder experience the cyclical nature of bipolar disorder but symptoms are chronic rather than severe.
We will soon have an entire section on bipolar and cyclothymic disorders posted on Bill Jacobs LPCC.