Bipolar Disorder is a type of mood disorder with marked changes in mood between extreme elation or happiness and severe depression. The periods of elation are termed mania. During this phase, the teenager has an expansive or irritable mood, can become hyperactive and agitated, can get by with very little or no sleep, becomes excessively involved in multiple projects and activities, and has impaired judgment. A teenager may indulge in risk taking behaviors, such as sexual promiscuity and anti-social behaviors. Some teenagers in a manic phase may develop psychotic symptoms (grandiose delusions and hallucinations). For a description of the depressive phase see depression. Bipolar disorder generally occurs before the age of 30 years and may first develop during adolescence.

For additional information see the following Facts for Families:
#38 - Bipolar Disorder (Manic-Depressive Illness) in Teens

Not only adults become depressed. Children and teenagers also may have depression, as well. The good news is that depression is a treatable illness. Depression is defined as an illness when the feelings of depression persist and interfere with a child or adolescent’s ability to function.

About 5 percent of children and adolescents in the general population suffer from depression at any given point in time. Children under stress, who experience loss, or who have attentional, learning, conduct or anxiety disorders are at a higher risk for depression. Depression also tends to run in families. Seriously depressed children and adolescents experience symptoms that are beyond the range of normal sadness.

For additional information see:

Facts for Families: The Depressed Child

AACAP Glossary of Symptoms and Illnesses—Symptoms of Depression

The National Institute of Mental Health Site on Depression in Children and Adolescents

National Alliance for Research on Schizophrenia and Depression (NARSAD), The World's Leading Charity Dedicated to Mental Health Research