When you have a mood disorder, your emotional state or mood is distorted or inconsistent with the circumstances and interferes with your ability to function. You may become extremely sad, empty inside, or irritable, and may show periods of depression alternating with periods of happiness (mania). A few examples of mood disorders include: • Major depressive disorder Prolonged periods of extreme sadness • Bipolar disorder Manic depression or bipolar affective disorder can include alternating times of depression and mania • Seasonal affective disorder Form of depression is often associated with fewer daylight hours in the far northern and southern latitudes happening from late fall to early spring • Cyclothymic disorder A disorder that can cause emotional ups and downs that are less extreme than bipolar disorder • Premenstrual dysphoric disorder Mood changes and irritability which occur around the premenstrual phase of a woman's cycle and go away with the onset of menses • Persistent depressive disorder Long-term form of depression • Disruptive mood dysregulation disorder Chronic, severe, and persistent irritability in children which often include frequent temper outbursts that are inconsistent with the child’s developmental age • Depression related to medical illness Persistent depressed mood and significant loss of pleasure in most or all activities that is directly related to the physical effects of another medical condition • Depression induced by substance use or medication Depressive symptoms that develop during or soon after substance use like drugs or alcohol or withdrawal or after exposure to a medication