Blood test could diagnose depression, predict treatment success

Scientists have discovered blood chemicals, the levels of which are higher in those suffering from depression, paving way for blood tests to diagnose the condition and even to say if one is biologically predisposed to feeling down.

In an attempt to drag depression out of the realm of mere assumptions, scientists from Northwestern University in Chicago, picked 32 people suffering from depression and matched them with 32 non-depressed counterparts of the same sex, age and race.

The researchers then measured levels of chemicals in the blood of the experiment participants and discovered the depressed group had higher levels of nine blood constituents.

Further measurements allowed researchers to single out three genes which “could possibly mark subjects with future recurrent depression.”

“These markers come closest to the ultimate goal of identifying predisposition to depression, even in the absence of a current depressive episode,” Eva Redei, who led the research, wrote in a paper published in Translational Psychiatry.

The experiment has also revealed a difference in certain blood patterns which could be used to tell those responding to psychotherapy from those not.

“This is a very promising finding as to date, there are no biomarkers or predictors of effectiveness of psychotherapy,” Redei believes.

Depression main cause of teen illness, suicide No. 3 cause of death – WHO

The scientist acknowledges more studies with a larger number of participants are needed to confirm the results of the research.

Redei has had a long record of studying depression, according to the Northwestern website. In 2009 she presented results of her experiments on rats, where she for the first time isolated blood constituents marking depression and anxiety.

In 2012, she made public the results of an experiment in which she took blood samples from 14 depressed and 14 non-depressed teenagers. She discovered 11 blood markers helping to differentiate between depressed and non-depressed adolescents.

“Right now depression is treated with a blunt instrument,” she said back then. “It’s like treating type-1 diabetes and type-2 diabetes exactly the same way.”

The latest research, which narrowed down the scope of blood chemicals signaling depression, had a much wider age range: from 23 to 83.

If further validated, the study could lead to a breakthrough in treatment of what the World Health Organization describes as the leading cause of disability globally. It’s estimated 350 million people worldwide suffer from depression.