4. Excessive late-night activities, too much or too little sleep, trouble getting up in the morning, often late for school.
5. Physical agitation or slowness, pacing back and forth and/or excessive, repetitive behaviors.
More from YourTango: Clueless Kathie Lee Gifford Asks Martin Short About His Dead Wife
6. Loss of energy, social withdrawal, withdrawal from usual activities, boredom.
7. Making critical comments about themselves, behavior problems at school or at home, overly sensitive to rejection.
8. Poor performance in school, drop in grades, frequent absences.
9. Frequent complaints of physical pain (headaches, stomach), frequent visits to school nurse.
10. Writing about death, giving away favorite belongings, comments like: "You'd be better off without me."
Depression often runs in families. The causes may be related to physical or sexual abuse or triggered a stressful life event like divorce, a death or a breakup. Whatever the cause, depression is a biological condition. It is not something to be ashamed of and it needs to be treated. A combination of medication and cognitive behavioral therapy is often recommended for teens.
It is essential that the whole family receives education and support, which is available through organizations like Families for Depression Awareness. They offer extensive resources on depression for teens, including a Teen Fact Sheet that this article draws from. 6 Things To Do If Your Teenager Terrifies You
More from YourTango: Photos: Sharon Stone, 54, Makes Out With 27-Year-Old Boyfriend
If you think your teen is depressed, get them evaluated. Ask for a referral to a mental health clinician from your doctor or nurse, a local mental health clinic or hospital, or a clinician listed on the Families for Depression Awareness website. Seek support and help from friends, clergy, and support groups.