Depression is a mood disorder that can affect people of all ages, including kids and teens.

The main sign of depression is a mood that's sad, discouraged, irritable, or hopeless &mdash and that lasts for weeks, months, or even longer. Another sign a kid might have depression is negative thinking. This includes focusing mostly on problems and faults, being mostly critical and self-critical, and complaining a lot.

>Depression can interfere with energy, concentration, sleep, and appetite. Kids with depression may lose interest in activities and schoolwork, seem tired, give up easily, or withdraw from friends or family.

More to Know

It's normal for kids to feel sad, down, or irritated, or to be in bad moods from time to time. But when these feelings linger for a long time and limit a child's ability to function normally, it might be depression or a similar mood disorder.

Doctors use different labels to diagnose mood disorders. These mood disorders all have depressed mood as a main symptom:

• Major depression — an intense episode of depression that has recently developed and has lasted for at least 2 weeks
• Chronic depression (also called dysthymia) — a milder depression that has developed more gradually, and has lasted for 2 years or longer
• Adjustment disorder with depressed mood — depression that has developed after an upsetting event (anything from a natural disaster to a death in the family)
• Seasonal affective disorder — a depression that is related to light exposure, and develops when hours of daylight are shorter; for example, during winter months
• Bipolar disorder (also called manic depression, bipolar depression) — a condition that includes episodes of major depression and, at other times, episodes of mania
• Disruptive mood dysregulation disorder — a pattern of intense, frequent temper tantrums, outbursts of aggression and anger, and a usual mood of irritability that has lasted for at least a year in a child older than 6

Keep in Mind

Treatment for kids and teens with depression and other mood disorders usually involves therapy (counseling with a psychologist or other mental health provider). Doctors and psychiatrists also can prescribe medicines for kids age 8 and older if they think these are needed. When depression is recognized and treated, kids and teens usually start to feel and do better.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.