Depression is rising among teenagers in the United States, especially among girls, a new study finds.

Between 2005 and 2014, the percentage of teens (ages 12 to 17) who reported having a major depressive episode increased from 8.7 percent to 11.3 percent, according to a study published last week in the journal Pediatrics.

A major depressive episode is defined by psychiatrists as a person having symptoms, such as feelings of emptiness, irritability or hopelessness that last for two weeks or more.

Girls, in particular, were more likely to report having had an episode of depression than boys the same age, researchers from Johns Hopkins Bloomberg School of Public Health in Baltimore found.  The percentage of major depressive episodes increased for girls from 13.1 percent in 2004 to 17.3 percent in 2014; boys, on the other hand, increased from 4.5 percent in 2004 to 5.7 percent in 2014.

The study is based on data from the National Surveys on Drug Use and Health.

The reasons for the increase in teen depression over the years are not entirely clear, but the study researchers suggested that the gender disparity may be tied to adolescent girls being more exposed to risk factors. For instance, they noted that cyber-bullying is much more prevalent among girls than boys.

Deborah Matek, MD, Head of the Division of Child and Adolescent Psychiatry at Cook County Health, said parents of teenagers should be aware of these warning signs of depression:

• An increase in irritability and impatience.  “This is the most typical mood swing for a depressed teen or child,” Dr. Matek said.
• Withdrawal from their friends and/or a change in their social crowd to a more rebellious, outsider group. 
• “Self-mutilating” behavior or scratching oneself to harm.  Hurting oneself is a risk factor for a suicide attempt, and it is often a sign of emotional distress.
• Changes in their eating habits that result in noticeable wait gain or loss or changes in their sleep patterns. 

• Sudden drop in their grades.  A student whose grades drop from their usual level, whether that is A’s and B’s to mostly C’s or from C’s to D’s and F’s, should be evaluated for depression, Dr. Matek said.

If a parent thinks their teen might be experiencing depression, especially if it lasts longer than two weeks, they should seek the help of a mental health professional, Dr. Matek said.

Clinical depression is a serious medical condition that requires immediate treatment.

To make an appointment with a child psychiatrist at Cook County Health, you can call 312-864-0200.