The study included 32 patients who had been independently diagnosed as depressed in a clinical interview and a non-depressed control group with the same number of patients. All of them ranged in age from 21 to 79. The patients were also participating in a previously reported study comparing the effectiveness of face-to-face versus telephone-administered cognitive behavioral therapy.
Prior to the therapy, the scientists found the 9 RNA blood markers at significantly different levels in the depressed patients than in the control group.
The blood concentration of three of the 9 RNA markers remained different in depressed patients and non-depressed controls, even if the depressed patients achieved remission from depression after the therapy. This appears to indicate a vulnerability to depression. “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,” Eva Redei, who developed the test and is a professor of psychiatry and behavioral sciences at the Northwestern University Feinberg School of Medicine, said in a statement. “This test brings mental health diagnosis into the 21st century and offers the first personalized medicine approach to people suffering from depression.”
Major depressive disorder affects almost 7% of the U.S. adult population annually. But diagnosis takes anywhere from two to 40 months, and the longer the delay, the more difficult it is to treat. An estimated 12.5% of primary care patients have major depression, with only about half of those cases diagnosed.
This test is expected to allow for more accurate, timely diagnosis. It could also help identify responders to cognitive therapy or those who could benefit from a particular drug therapy. In addition, it could enable closer monitoring and treatment of people prone to depression. Redei previously developed a different blood test to be used to diagnose adolescent depression; interestingly, most of the markers she identified for the adult depression panel are different from those for depressed adolescents.
Next, Redei plans to test the results in a larger population; she also wants to see if the test can distinguish between major depression and bipolar depression. The study was supported by grants from the National Institute of Mental Health of the U.S. National Institutes of Health and the Davee Foundation.
REFERENCE: Fierce Medical Devices; 17 SEP 2014; Stacy Lawrence