Remarkable Promise:  
A New Blood Test for Major Depressive Disorder

The Annual Physical

Every year I go to my doctor for my annual physical, and she performs a standard run-of-the-mill exam, and I leave the office to get various other tests run.  When I was younger, all I needed was some additional lab work. As I’ve gotten older, I now have the pleasure of receiving a mammogram and colonoscopy as part of my “routine” check-up.  In a week or two, I end up going back and inevitably finding out that my cholesterol is high, or my hormones are out of whack, or some such information that requires a prescription and more follow up exams.  I leave grateful, because had I not had those tests, I may not have known I was suffering from those ailments and they would be left to do their damage over time.

A Missing Piece

One thing I know my doctor doesn’t test for is depression.  Quite honestly, the screening questions she asks about my sleep patterns, appetite, etc., aren’t all that accurate.  There are plenty of other illnesses that have the same symptomatology as depression, so a diagnosis of depression, and perhaps a prescription of an antidepressant may not do anything more than give me more pills with side effects that I don’t want. On the other hand, they might be just what I need.  How can I know with certainty?

Current methods of diagnosing depression are completely 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. Being able to come up with a diagnosis also requires the patient to report their symptoms and for the physician to accurately interpret them. But depressed patients frequently underreport or inadequately describe their symptoms.

Major depressive disorder (MDD) affects 6.7 % of the U.S. adult population in a year, a number that is climbing. An estimated 12.5% of patients in primary care have major depression but only about half of those cases are diagnosed. Using conventional testing it can take from 2 to upwards of 40-months to diagnose MDD, and the longer the delay, the more difficult it is to treat. A recently discovered, biologically based test has the potential to provide a more timely and accurate diagnosis.

A Rapid Test for Depression - Blood Samples

The first blood test to diagnose major depression in adults has been developed by scientists at Northwestern University. This test provides the first objective, scientific diagnosis for depression. The test identifies depression by measuring the levels of nine RNA blood markers, which are messenger-molecules that interpret the DNA genetic code and carry out its instructions.

Eva Redei, who developed the test and is a professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine explains, "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, 2014, in Translational Psychiatry.  "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 Reidel.

The blood concentration of three of the nine 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.  "These three markers move us towards the ultimate goal of identifying predisposition to depression, even in the absence of a current depressive episode," said Redei.  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.  Redei explained, "This distinction could be used in the future to predict who would respond to the therapy." 

The Future of Depression Diagnosis

Co-lead author on they study, David Mohr, a professor of preventive medicine and director of the Center for Behavioral Intervention Technologies at Feinberg states, "Mental health has been where medicine was 100 years ago when physicians diagnosed illnesses or disorders based on symptoms. This study brings us much closer to having laboratory tests that can be used in diagnosis and treatment selection."  Mohr explained that "Currently we know drug therapy is effective but not for everybody and psychotherapy is effective but not for everybody,  . . . We know combined therapies are more effective than either alone but maybe by combining therapies we are using a scattershot approach. Having a blood test would allow us to better target treatment to individuals . . . Being aware of people who are more susceptible to recurring depression allows us to monitor them more closely," Mohr noted. "They can consider a maintenance dose of antidepressants or continued psychotherapy to diminish the severity of a future episode or prolong the intervals between episodes."

This study brings great news for patients and primary physicians alike. A blood test that can diagnose depression, determine potential treatment protocol and response can and will lend a much higher success rate to any depression diagnosis.  Purely subjective and error-prone diagnoses will soon hopefully, be a thing of the past as the treatment for depression finally moves forward into the 21st century.  Routine lab tests will soon direct effective and accurate treatment for not just our physical health, but our mental health as well. 

- Laura Wells


Insightful Comments


In today’s medically astute population there is a cliché that floats about - “There’s a pill for that.” I know that at least my former physician was very good with that form of treatment. However, it seems as though the cliché is very accurate. If there is not a pill for that or a cream for that, then there is certainly a test for that.  For now I prefer to refrain from discussing my thoughts on the issues of the collusions of physicians and pharmaceutical companies. 

As we all know there is a test for the Human Immunodeficiency Virus, HIV, that causes the Acquired Immune Deficiency Syndrome, AIDS, disease. However, as of this writing, despite all of the publicity, money, and research devoted to finding a cure or even a vaccine there is no such cure. We are light years ahead of where we were back in the 1980s and early 1990s, but we still currently have a test and some experimental treatments, but no cure.

If I go to my doctor and present general symptoms of sickness, in most cases, he will prescribe some medication in some form be it topical, oral, or injection. The diagnosis may or may not be made on the basis of a biopsy, blood, urine, skin, spinal, or any other test. Frequently the test results are never questioned or examined any further than a range of numbers. If my numbers are on the borderline then I may or may not be diagnosed as having the ‘XYZ’ disease.  This brings us to the point at which I have aggravated more than one physician in conversation. I have argued the point that in today’s medical society the practice of medicine is nothing more than a sophisticated gamble. 

A doctor is presented with a medical case and often without even seeing and/or really meeting or getting to know the patient, he/she will prognosticate a diagnosis. Then the physician will often send the patient out for further testing. The result often equals a new medication or an additional medication to an already over prescribed medicinal regimen. “Go ahead and start this medication and we’ll see how it goes for a few weeks or months,” is one of the most frequent phrases in the examination room. 

Now, I am not an idiot. I know that medical services cost a great deal of money and that many, if not most, insurance companies will not cover the cost of the treatment that most, if not everyone, really deserve. However, it seems as though I am thought of as an idiot and/or a fool for expecting real and adequate treatment for every part of my life. The physical, emotional, mental, and spiritual ailments that plague me and everyone else deserve the best available care and not just a gamble through testing. 

Northwestern University. (2014, September 17). First blood test to diagnose depression in adults. ScienceDaily. Retrieved December 10, 2014 from www.sciencedaily.com/releases/2014/09/140917121229.htm