Depression is a type of mental illness that sometimes affects children, causing them to feel sad, angry or frustrated for long periods of time. Major depression among children affects about 2 percent of children ages 6 to 12 years and 4 percent of adolescents, according to the National Alliance on Mental Illness (NAMI).

Some bouts of depression in children are severe but relatively short in duration. Others are mild, but may continue for years. Children may become depressed after a trauma, such as the death of a parent, family strife or illness. In other cases, the source of this change in mood is less obvious.

Experts classify depression in many different ways. The two general categories of depression are:

• Major depression. Also known as clinical depression or unipolar depression, it is a severe type of depression that requires treatment. Most patients who experience a bout of major depression are likely to have recurrent bouts in the future. 
  
  
• Bipolar disorder. Formerly known as manic depressive illness, it involves alternating periods of extreme highs (mania) and extreme lows (depression). Youth symptoms related to bipolar disorder differ somewhat from those experienced by adults. 

Experts may also use other categories to classify certain types of depression. They include:

• Dysthymia. A chronic form of low-level depression that lasts for at least two years. Children with dysthymia have a perpetually gloomy mood.
  
  
• Adjustment disorder with depressed mood. A bout of depression that occurs after a significant life change, such as the death of a loved one or a major disaster.

The causes of depression are not fully understood. Changes in brain chemistry appear to be responsible. In some children, depression may have a genetic link.

Depressed children may experience ongoing sadness, irritable mood and a sense of overall hopelessness. They may have little interest in new activities, and may no longer enjoy activities that previously provided them with pleasure. These children may have difficulties at school, somatic complaints, and aggressive or antisocial behavior patterns. Some may experience weight changes or disruption in their sleep patterns. Many depressed children complain of persistent boredom and may exhibit low levels of energy. They may even talk about wishing they were dead, or may make similar statements that indicate suicidal thoughts. 

Parents are urged to seek medical attention for any child who exhibits symptoms of significant depression that appear to be negatively impacting the child’s quality of life. If the physician suspects that a child is depressed, the patient may be referred to a child and adolescent psychiatrist or other mental health professional for further evaluation and treatment. 

Treatments for depression in children usually consist of psychotherapy, medications or a combination of the two. Psychotherapy may consist of individual therapy and family therapy, and antidepressants typically are the medication of choice in treating depression.

It is important to note that the U.S. Food and Drug Administration has advised that antidepressants may increase the risk of suicidal thinking in some patients, especially children and adolescents, and all people being treated with them should be monitored closely for unusual changes in behavior.