If you have a mood disorder, your general emotional state or mood is distorted or inconsistent with your circumstances and interferes with your ability to function. You may be extremely sad, empty or irritable (depressed), or you may have periods of depression alternating with being excessively happy (mania). Anxiety disorders can also affect your mood and often occur along with depression. Mood disorders may increase your risk of suicide. Some examples of mood disorders include:
Major depressive disorder — prolonged and persistent periods of extreme sadness
Bipolar disorder — also called manic depression or bipolar affective disorder, depression that includes alternating times of depression and mania
Seasonal affective disorder (SAD) — a form of depression most often associated with fewer hours of daylight in the far northern and southern latitudes from late fall to early spring
Cyclothymic disorder — a disorder that causes emotional ups and downs that are less extreme than bipolar disorder
Premenstrual dysphoric disorder — mood changes and irritability that occur during the premenstrual phase of a woman’s cycle and go away with the onset of menses
Persistent depressive disorder (dysthymia) — a long-term (chronic) form of depression
Disruptive mood dysregulation disorder — a disorder of chronic, severe and persistent irritability in children that often includes frequent temper outbursts that are inconsistent with the child’s developmental age
Depression related to medical illness — a persistent depressed mood and a significant loss of pleasure in most or all activities that’s directly related to the physical effects of another medical condition
Depression induced by substance use or medication ― depression symptoms that develop during or soon after substance use or withdrawal or after exposure to a medication.
Source: Mayo Clinic