What is the definition or description of: mood swings?

Varying emotions: Mood swings are common among people who suffer from depression. They can be described as an alternating emotional state that include periods of euphoria and depression.

Mood swings.: I read the description of mood swings as alternating between euphoria and depression. I would add to this that sometimes mood swings are not this extreme. Moods may be bored, mildly unhappy, irritable, sad, or back to "okay" or stable. Extreme mood swings are those in bipolar mania and depression.