Periods of variation in how one feels, changing from a sense of wellbeing to one of depression. This occurs normally, but may become abnormally intense in persons with manic-depressive states.
Swift shifts in emotions are termed mood swings. Mild mood swings, like transitioning from feeling calm to anxious, irritable, or tearful, can manifest in women with premenstrual syndrome or those experiencing menopause. On the other hand, severe mood changes, ranging from mania (unusually heightened activity and joy) to depression, are linked to bipolar affective disorder.