April 17, 2012 -- Scientists have developed a blood test that may help diagnose major depression in teens and young adults.
The test is in very early stages. However, scientists hope it will someday make diagnosing depression more objective for teens.
"The bottom line is that a test is possible from blood that can differentiate teens with major depression from those who do not have it," says scientist Eva Redei, PhD, professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine.
The findings are published in Translational Psychiatry.
It's crucial to point out that the study is very preliminary and not ready for clinical use, says Alexander B. Niculescu III, MD, PhD, associate professor of psychiatry and medical neuroscience at Indiana University School of Medicine. He is also researching blood tests for depression and other mood disorders.
Major depression affects about 1% of children under age 12, Redei says.
By late teens and young adulthood, that figure rises to about 25%. If it is untreated in teens, their risk of substance abuse, suicide, physical illness, and other problems goes up, Redei says.
Doctors diagnose depression by asking about symptoms. These can include feeling sad or blue for an extended period of time, withdrawing from activities or friends, and suddenly doing poorly at school. When teens talk to a doctor, they may not communicate well, Redei says. "This is the generation, the age group that needs the most help," Redei tells WebMD.
Blood Test for Depression
Redei's team focused on 26 blood biomarkers, or indicators, for depression and anxiety. These indicators reflect the activity of genes related to depression.
They tested these indicators in 14 teens with major depression who had not been treated and 14 teens who were not depressed.
They found that 11 of the indicators were linked to depression, and 18 were linked to anxiety as well as depression. It is too early to say that the test works in a specific percentage of people, Redei says. "You need much larger studies," she tells WebMD.
Niculescu agrees that larger studies are needed. Scientists must reproduce the findings. They need to calculate accuracy.
"That is the gold standard," he says. "We need to be careful not to jump to conclusions based on a small number of study participants." The blood markers for depression vary a lot in the population, he says.
Niculescu reports serving on the speaker's bureau for Janssen and Sunovion Pharmaceuticals.