Mood disorders are sometimes called affective disorders. Affect (emphasis on the first syllable) means emotional state as revealed through facial expressions and gestures.
Sadness and joy are part of the normal experience of everyday life and differ from the depression and mania that characterize mood disorders. Sadness is a natural response to loss, defeat, disappointment, trauma, or catastrophe.
Grief or bereavement is the most common of the normal reactions to a loss or separation, such as the death of a loved one, divorce, or romantic disappointment. Usually, bereavement and loss do not cause persistent, incapacitating depression except in people predisposed to mood disorders.
A mood disorder is diagnosed when sadness or elation is overly intense, is accompanied by certain other typical symptoms, and impairs the ability to function physically, socially, and at work.
When only depression occurs, it is termed a unipolar disorder. Other mood disorders, termed bipolar disorders, involve episodes of depression alternating with episodes of mania. Mania without depression (called unipolar mania) is very rare.
About 30% of people report depression as one of their symptoms when they see their doctor. But fewer than 10% actually have severe depression. Nearly 4% of the U.S. population have a bipolar disorder.
Mood disorders in children and adolescents can also occur.
Having a mood disorder, particularly one that involves depression, increases the risk of other problems, such as inability to do daily activities and maintain relationships, loss of appetite, extreme anxiety, and alcohol use disorder. As many as 15% of people with untreated depression end their life by suicide.
Mental Health America (MHA): Community-based nonprofit organization that promotes mental health as a critical part of overall wellness and provides educational materials and information on public policy
National Alliance on Mental Illness (NAMI): Largest grassroots mental health organization in the United States dedicated to improving the lives of people living with mental illness
National Institutes of Mental Health (NIMH): General information on many aspects of mental illness, including research, legislation, and outreach