Too many teens who are depressed are undiagnosed and untreated, according to a national health task force.

The U.S. Preventive Services Task Force recommends that all adolescents receive regular screenings for depression as part of their overall health care.

Depression affects 5-10 percent of teens and 20 percent of people of all ages at some point in their lives, according to Dr. Dale Peeples, a child and adolescent psychiatrist at Medical College of Georgia Hospital and Clinics.

You might notice it in a friend.

"In some ways, teens may be in a better position even than their parents to judge," Dr. Peeples said.

As friends become more important, teens naturally pull away from parents, he said.

Friends might be able to tell whether the withdrawal is out of the ordinary, according to the psychiatrist.

A teen should urge a friend exhibiting symptoms of depression to talk to his or her family and a doctor.

"Just being a good friend isn't going to pull someone out of a depression," Dr. Peeples said.

There's a difference between depression and just being sad. After a major change or event such as the death of a grandparent, it is normal to be sad. "You expect someone to gradually move out of that state," Dr. Peeples said.

Duration is another determinant. If people are sad for two weeks or more, they might be suffering from depression, he said.

Kenron Hackett, 18, a home-schooled graduate who will attend Augusta State University in the fall, said he thinks an across-the-board screening is fine.

"You go to the doctor whether you're sick or not," he said.

Everyone should know about certain illnesses or health issues, he said, and that would be one way to do it.

Reach Sarah Day Owen at (706) 823-3223 or sarah.owen@augustachronicle.com.