The first blood test to diagnose major depression in adults has been developed by Northwestern Medicine® scientists, a breakthrough approach that provides the first objective, scientific diagnosis for depression. The test identifies depression by measuring the levels of nine RNA blood markers. RNA molecules are the messengers that interpret the DNA genetic code and carry out its instructions.


The blood test also predicts who will benefit from cognitive behavioral therapy based on the behavior of some of the markers. This will provide the opportunity for more effective, individualized therapy for people with depression.


In addition, the test showed the biological effects of cognitive behavioral therapy, the first measurable, blood-based evidence of the therapy’s success. The levels of markers changed in patients who had the therapy for 18 weeks and were no longer depressed.  


“This clearly indicates that you can have a blood-based laboratory test for depression, providing a scientific diagnosis in the same way someone is diagnosed with high blood pressure or high cholesterol,” said Eva Redei, who developed the test and is a professor of psychiatry and behavioral sciences at Northwestern's Feinberg School of Medicine. “This test brings mental health diagnosis into the 21st century and offers the first personalized medicine approach to people suffering from depression.”


Redei is co-lead author of the study, which was published September 16 in Translational Psychiatry.


Redei previously developed a blood test that diagnosed depression in adolescents. Most of the markers she identified in the adult depression panel are different from those in depressed adolescents.


The search for a biological diagnostic test for major depression has been ongoing for decades.


The current method of diagnosing depression is subjective and based on non-specific symptoms such as poor mood, fatigue, and change in appetite, all of which can apply to a large number of mental or physical problems. A diagnosis also relies on the patient’s ability to report his symptoms and the physician’s ability to interpret them. But depressed patients frequently underreport or inadequately describe their symptoms.


“Mental health has been where medicine was 100 years ago when physicians diagnosed illnesses or disorders based on symptoms,” said co-lead author David Mohr, a professor of preventive medicine and director of the Center for Behavioral Intervention Technologies at Feinberg. “This study brings us much closer to having laboratory tests that can be used in diagnosis and treatment selection.”


Visit the Northwestern News Center for the full story.


For more stories from this month's Alumni News, visit the NAA on Our Northwestern, the University's online community.