Mood disorders refer to a category of mental health problems that include four basic forms of mood disorders: Major Depression, cyclothymia, Seasonal Affective Disorder, and Mania.

During the 1980s, mental health professionals began to recognize symptoms of mood disorders in children and adolescents, as well as adults. However, children and adolescents do not necessarily experience or exhibit the same symptoms as adults. It is more difficult to diagnose mood disorders in children, especially because children are not always able to express how they feel. Today, clinicians and researchers believe that mood disorders in children and adolescents remain one of the most under-diagnosed mental health problems. At any age, mood disorders put individuals at risk for other conditions that may persist long after the initial episodes of depression are resolved.