"Mood swings, or rapid changes in one's emotional state, may occur as a reaction to circumstances or environment, as a result of a physical or mental health condition, or for no apparent reason. General moodiness is likely to be a part of everyone's life, but in some circumstances, changes in mood may be severe and have an effect on health and daily function. When rapid or frequent mood shifts seem to occur without a cause or when they affect one's behavior, well-being, or typical function, the support of a therapist or other mental health professional may be helpful. "