TUESDAY, April 17 (HealthDay News) -- Researchers have developed
a blood test that could one day help diagnose teens with
To create the test, researchers identified 26 potential
biological markers for depression. Then they tested the markers in
a small group of teens and found that a handful of them could
distinguish the teens with major depression from those without
The research was published April 17 in the journal
"I think it would be more accurate to diagnose depression with a blood test," said study author Eva Redei, a professor of psychiatry at Northwestern University Feinberg School of Medicine. The biomarkers now have to be studied in a larger group of teens, she added.
Currently the diagnosis for depression is subjective and
involves doctors talking with patients about their moods. The
evaluation is especially tricky in teens because this is a trying
time emotionally to start with, Redei said.
Having an objective diagnosis that relies on biomarkers could
also make it an easier diagnosis for teens to hear and ease some of
the stigma associated with depression.
"It would bring this disease into the same family of other serious illnesses," Redei said. "It would be much more difficult for somebody to say, 'Just snap out of it' or 'Get yourself together.'"
Between 17 percent and 25 percent of adolescents and young
adults experience depression, according to study background
information. Teens who develop depression have a worse prognosis,
marked by illness, substance abuse and suicidal behavior, compared
to people who are diagnosed later in life.
The current study involved 28 white and black teens in the
Chicago area. Half of the teens had depression.
The researchers compared the levels of the 26 potential
biomarkers in blood samples from the teens and found that 11 of
them were present at higher or lower levels among the teens with
In addition, they found that 18 of the biomarkers could
accurately predict whether teens with depression also had an
In a clinical setting, a screening test for depression would
involve a panel of biomarkers, Redei explained. Some of them would
give the doctor a yes/no answer about whether the teen could have
depression and should be further evaluated, while others could
reveal information about the depression and how to treat it, such
as its severity and whether it is accompanied by anxiety.
"The hope is that not only can these tests identify who is depressed, but they also potentially discriminate between different types of depression," Redei said.
But first Redei's group has to determine whether their
biomarkers are accurate in a large group of teens representing a
range of racial backgrounds and from different areas of the
country. They are now beginning these studies.
Larger studies will tell us a lot about how useful these
biomarkers could be, said Dr. Sheldon Preskorn, a professor of
psychiatry at the University of Kansas School of Medicine-Wichita.
Anytime you test a number of potential biomarkers on a small group
of people you are going to find some biomarkers that look
clinically important, he added.
But having a screen to help identify who has depression could be
hugely helpful, Preskorn said. "This kind of approach is somewhat
the holy grail of psychology."
There are as yet no biomarkers available for diagnosing
depression at any age.
Redei's group is also testing the biomarkers in adults. Although
it is too soon to tell for sure, she thinks that some will end up
being helpful for diagnosing depression in adults.
The group originally identified the set of 26 candidate
biomarkers by studying rats with conditions that mimic depression
in humans. And like in humans, the condition in rats is linked
either to genetic or environmental factors.
The researchers looked in these animals at a type of molecule
called a transcript, which is an intermediate molecule between a
gene and its corresponding protein. Differences in the level of
transcripts indicate changes in gene expression.
They found 11 transcripts that were different in the blood and
brain of animals that were bred to be in a perpetual state of
depression compared to normal animals. In addition, they found 15
transcripts that increased or decreased in groups of rats with
Altogether the changes that the researchers found were in genes
that were "most unexpected," Redei said, adding that, "This just
characterized how little we know about depression."
The discovery of these biomarkers gives researchers a new list
of targets to pursue as potential antidepressants, Redei said.
Having a reliable blood-based diagnostic for depression could
also open the door to treating people before symptoms appear,
Preskorn said. "You might want to look at high-risk populations,
like if you have a family history of depression."
This approach is similar to how doctors manage other conditions
like heart disease, Preskorn said. "If you know that a person has
high cholesterol and high lipids, then you don't wait till the
person develops atherosclerosis to start the statin drug."
You can learn more about diagnosing depression at
the U.S. National Institute of Mental Health.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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