Mood variability is something which might apparently common in general population. Mood variability refers to the frequent change in the mood of person with bare minimum or without external stimulation. Mood variability has been studied in relation to a range of clinical disorders. The notable ones are Bipolar Disorder, Borderline Personality Disorder, Major Depressive Disorder, Premenstrual Syndrome and Post-Traumatic Stress Disorder. The study that was conducted by Benedetti et al. (1996) investigated fluctuations in mood in a clinical sample.
The sample included Bipolar Depressive patients and patients with recurrent Major Depressive Disorder. Through post hoc analysis, they found that those in their sample who depicted higher levels of variability in mood had a longer duration of a depressive episode, they had comparatively a longer hospital stay and severe depressive episode. These patients also exhibited the signs of relapse more often than those without mood variability.