Mood Disorders are an overarching category of several different disorders, including Major Depressive Disorder (MDD), Persistent Depressive Disorder, Bipolar Disorders, Disruptive Mood Dysregulation Disorder (DMDD), and Premenstrual Dysphoric Disorder (PMDD). MDD is the most common mood disorder, characterized by at least two weeks of persistent low mood or loss of interest in typical activities in addition to at least four other symptoms (sleep disruption, guilty thoughts, low energy, poorer concentration, changes in appetite, agitation or lethargy, and suicidal ideation). While MDD tends to be episodic, Persistent Depressive Disorder (PDD) is more chronic, with low mood or irritability occurring more days than not for at least two years. Symptoms of PDD tend to be less severe than those of MDD. Bipolar Disorders (including Bipolar I, Bipolar II, and Cyclothymia) are all characterized by interfering and often distressing episodes of hypomania/mania and low mood/major depression (depending on the disorder type). Please see “Associated Conditions” for more information on these types of mood episodes.
