Blood test for teenage depression

Teenagers are vulnerable to depression. Image: Alexandra Thompson/Shutterstock

Your blood can tell a doctor if you’re depressed.

Scientists from the Northwestern University Feinberg School of Medicine in the US have developed the first blood test for diagnosing depression in teenagers. The study published in Translational Psychiatry used specific markers found in a patient’s blood to develop the measurements.

Diagnosing depression is currently a subjective process, as it relys on the patient’s ability to recount their symptoms and the physician’s ability to interpret them. Teenagers are also highly vulnerable to depression, with the estimated rates of major depressive disorder increase from two to four percent in pre-adolescent children to 10 to 20 percent by late adolescence.

“”Right now depression is treated with a blunt instrument,” lead investigator Professor Eva Redei said. “It’s like treating type 1 diabetes and type 2 diabetes exactly the same way. We need to do better for these kids.”

Teenagers are also undergoing normal mood changes at this age, making accurately diagnosing them a challenge.

The study focused on 14 adolescents with major depression who had not yet been clinically treated and 14 adolescents who weren’t suffering from depression. The subjects were all between 15 and 19 years old and were matched according to race and sex.

Redei tested their blood for 26 candidate markers that had been previously identified from rats. The markers are products of genes that are present in a larger or smaller quantity in the blood of teenagers with major depression, as compared to the non-depressed controls.

“Eleven of these markers could differentiate teens with depression from those without the disease.”

In addition, six of these 11 markers and 12 others could distinguish between adolescents who had major depression only, and those who had major depression combined with anxiety disorder

“These 11 genes are probably the tip of the iceberg because depression is a complex illness,” Redei said. “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.”

A blood test could provide an objective measure that can assist physicians, particularly in cases with difficult diagnosis. Redei said that this test could be in the not-too-far future, assuming they will have sufficient resources to recruit a larger number of subjects.

The depressed subjects all chose not to undergo treatment after the study. “Everybody, including parents, are wary of treatment, and there remains a social stigma around depression, which in the peer-pressured world of teenagers is even more devastating,” Redei said.

“Once you can objectively diagnose depression as you would hypertension or diabetes, the stigma will likely disappear.”