Blood Test Diagnoses Depression In Teens

Diagnosing depression may soon include a simple blood test, according to research published Tuesday. new study. Researchers developed a blood test to identify markers for depression in teenagers that maylead to better treatments and lessen the stigma surrounding the condition.

Doctors currently rely on patients coming forward with symptoms to diagnose depression. However, differentiating between types of depression can be difficult without an objective diagnosis, researchers said. Instead, using a diagnostic blood test could allow for more personalized treatment.

"Right now depression is treated with a blunt instrument," Dr. Eva Redei, study author and professor of psychiatry at Northwestern University, said in a statement. "It's like treating type 1 diabetes and type 2 diabetes exactly the same way. We need to do better."

Previous studies identified 26 potential genetic markers for depression in rats. Redei and her team found 11 similar markers in depressed teens that they did not find in the control group.

"These 11 genes are probably the tip of the iceberg because depression is a complex illness," Redei said in a statement. "But it's an entree into a much bigger phenomenon that has to be explored. It clearly indicates we can diagnose from blood and create a blood diagnosis test for depression."

Some doctors remain skeptical of the findings since the study examined only 28 volunteers. Skeptics said research needs to show whether the markers can test a wider population and whether the markers are present in adults as well before the test can be considered viable.

"I think people are looking for a magic bullet, a single answer," Dr. Carol Bernstein, an associate professor of psychiatry at New York University, told ABC News. "But these disorders are much too complicated."

One in 20 Americans over the age of 12 reported feeling symptoms of depression between 2005 and 2006, according to the Centers for Disease Control and Prevention. Symptoms include hopelessness, feeling like a failure, poor appetite and lack of interest in activities.

Depression affects approximately 1 percent of children under the age of 12, researchers said. But as children enter their teenage years, depression affects almost 25 percent. Depression that sets in during the teenage years has a poorer prognosis than depression that sets in in adulthood, increasing the risk of substance abuse, suicide and physical illness, researchers said.

Being able to diagnose depression with a blood test could mean more people getting treatment. None of the teens who were diagnosed with depression over the course of the study opted for treatment, most likely due to the stigma that comes with it, Redei said.

Depression is treated through a combination of medication and therapy, but many people see the disease as a defect and think it will make people view them as "broken", Dr. Jonathan Rottenberg, an associate professor of psychology at the University of South Florida, said in a Psychology Today blog post.

 The journal Translational Psychiatry published the study on Tuesday.

Preeclampsia Study suggests origins of pregnancy-linked high blood pressure

Preeclampsia, a potentially dangerous spike in blood pressure during pregnancy, may be due to a microscopic battle going on within the placenta between cells directed by the father's genes and those directed by the mother, a new study suggests.

Though not the first research to link preeclampsia with the activity of cells in the placenta, the new report adds more details about the underlying mechanism that may be causing the problem.

During prenatal growth, certain genes are expressed or repressed, depending on their parental origin. In the placenta, the father's gene expression dominates.

In a normal pregnancy, trophoblasts, a father-directed cell, invade and attack the blood vessels that bring blood from the mother into the placenta. The trophoblasts attach to the walls of blood vessels, increasing the flow of blood and enabling the baby to grow and receive the nutrients it needs to thrive, explained study author Dr. Harvey Kliman, a research scientist in the department of obstetrics, gynecology and reproductive sciences at Yale University School of Medicine.

But at the same time, the mother's immune system cells (lymphocytes) rush to kill the invasive trophoblasts. If the lymphocytes succeed in killing the trophoblasts, then there isn't enough blood flow to the placenta -- causing blood pressure to rise.

"The placenta is responsible for keeping the fetus alive. It will do whatever is necessary to do that," Kliman said. "The placenta has a sensor, a molecular mechanism that senses how much blood is flowing into the placenta. If there's not enough blood, you will become hypertensive."

Though his research didn't investigate that mechanism specifically, it's well known that an obstruction to blood flow to another organ, the kidney, leads quickly to primary renal hypertension, a type of high blood pressure. The placenta, he says, has a similar internal thermostat. If it's not getting enough blood, blood pressure goes up in an attempt to get more blood into the organ and prevent the fetus from dying.

So, to outwit the mother's lymphocytes, the father's trophoblasts create a diversion. Trophoblasts make a protein (PP13), which exits the blood vessels and travels into the lining of the uterus.

The lymphocytes rush to deal with that inflammation, ignoring the trophoblasts.

"All of the mother's soldiers are being diverted and focusing on the PP13 instead of going after the trophoblasts," Kliman said. "It's very sneaky."

The findings are published in the Oct. 11 online issue of Reproductive Sciences.

In the study, researchers used placental tissue from women in the United States and Israel.

Prior research had found that when levels of the PP13 protein are low early in pregnancy, women were more likely to develop preeclampsia several months later, but why PP13 contributed to that wasn't understood.

Kliman said the molecular battle is driven by the father-directed trophoblasts, which are trying to create conditions for a big, healthy baby, while mother needs to tamp down on growth so that the fetus is small enough to get through the birth canal.

"The mother does not want to die. The father wants a big baby. So they compromise," he said. "If the invasive trophoblasts are killed, the blood vessels wouldn't open up, and the baby would die. If the father wins the battle and the trophoblasts are able to go into the uterus, the baby would grow too big and the woman would die."

Dr. Jill Rabin, chief of ambulatory care in the obstetrics and gynecology department and head of urogynecology at Long Island Jewish Medical Center in New Hyde Park, N.Y., said the research adds "teeth" to the theory of the role of trophoblasts in preeclampsia.

"It makes a lot of sense that the mother's immune system had to be tricked somehow, otherwise how would this happen that a placenta or a fetus could set up housekeeping inside the mother?" Rabin said. "The placenta is very smart."

Eventually, the hope is that understanding the underlying biological mechanism that causes preeclampsia will lead to treatments, Rabin said, adding that more studies are needed to confirm the findings.

Preeclampsia usually shows up in the latter half of pregnancy. Many cases are mild, but it can progress to eclampsia, or severely elevated blood pressure and protein in the urine that can lead to seizures and puts a woman at risk of stroke or organ damage. The only cure for it is to deliver the baby, experts said.

Read more about Preeclampsia on the UK NHS website

Obesity Lower at High Altitude

People who are classified as Obese may find it easier to lose weight at high altitudes, the results of a German study suggest.

Previous studies demonstrated weight loss in athletes and normal-weight subjects at high altitude, but this study focused on the impact of altitude on overweight people for whom weight loss is desirable.

Researchers from Germany took 20 obese men to a high altitude location for one week. No changes were made to limit their food or alter their exercise routines, in an attempt to isolate the impact of altitude on weight.

After one week, the participants were eating less, had lost weight and had a lower diastolic blood pressure.

Writing in Obesity, the researchers said that low levels of oxygen found at high altitude may cause a rise in the hormone leptin which is thought to suppress appetite. However, they say more research is needed.

- Obesity Online 2010
- American Obesity Association

- AOA Online Journal
- The Journal of the American Obesity Association