The happy times for a teenager can be utterly sensational but the “down times” are very real as well. One national survey reported that many teens experience feelings of depression and sadness that often go untreated and that 9 out of 10 adolescents have periods of depression that last at least two weeks.

So, what’s a parent to do? Well, a good place to start is identifying whether or not your child has a problem. And, to do that, it’s worth considering how many different types of depression there are.

There are actually four varieties of the illness:

Reactive Depression The most common form of mood problem in children and adolescents, it’s also the least serious. Reactive Depression is a depressed state brought on by difficulty adjusting to a disturbing circumstance. This could involve something as serious as the loss of a parent or as relatively inconsequential as a rejection or slight from a good friend. It usually lasts anywhere from a few hours to a couple of weeks, but it’s not considered to be a mental disorder.

Bipolar Disorder Also known as “manic depression,” this is characterized by unusual shifts in mood and energy. Though not as common in young people, the condition frequently begins with a depressive episode during adolescence.

Dysthymic Disorder A milder but more chronic depression also known as “dysthymia.” It is a low-level depression that is felt most of the day most days, and continues for years. In adolescents, the average duration is four years – meaning that they spend virtually their entire adolescence in a depressed state.

Major Depressive Disorder A serious depression that in adolescents lasts for seven to nine months on average. It has many similarities to adult depression—sadness, pessimism, sleep and appetite disturbance—but in other ways it is distinct. (For example—anxiety symptoms and irritability are more common in depressed teenagers than adults.)

Adolescents frequently have the “atypical” form of MDD. This is characterized by being overly sensitive to the environment and responding to perceived negative interactions, with symptoms opposite from the “classic” picture (e.g. overeating or sleeping too much, rather than too little).

NOTE: Double Depression is a combination of Dysthymic Disorder and MDD—a depression that is both serious and chronic.

So . . . how can you tell if your teenager is depressed?

1. Is he or she always sad or in an irritable mood?

2. Has he or she lost interest in something he or she previously enjoyed?

3. Have you noticed a significant change in his or her eating patterns? (Has your son seemed to “lose” his appetite—or has your “figure-conscious” daughter become a “chow hound?”)

4. Is your former “early riser” now sleeping in considerably longer?

5. Does he or she have trouble concentrating on projects that “never used to be a problem before?”

6. Has your son or daughter recently begun expressing feelings of worthlessness or inappropriate guilt?

7. Do they fear death?

8. Is your son or daughter experiencing excessive boredom?

9. Is your son or daughter prone to sudden outbursts of shouting, complaining, unexplained irritability or crying?

10. Has your son or daughter recently begun complaining about frequent vague, unspecific physical ailments?

If anything on the list applies to your child, he or she may be dealing with depression. Get help—and get it today!