Depression affects children and adolescents, but is as much as 4X more common in adolescents.

What are some of the signs of this mood disorder:

• overwhelming feelings of sadness 
• loss of pleasure or hopelessness
• school based problems
• sleep problems 
• difficulty concentrating
• fatigue and low energy
• changes in appetite
• thoughts of death or suicide

In adolescents, your pediatrician can rule out a drug/alcohol problem or a hormone problem (ie decreases in thyroid function or hypothyroidism) with some simple laboratory tests before a diagnosis can properly be made.