Finding Depression In The Blood Stream Dr. David Mohr developed a new blood test that can potentially be used to diagnose depression. He talks with NPR's Arun Rath about the implications this discovery could have on the disease and treatment.

Finding Depression In The Blood Stream

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


Major depression is one of the most common mental disorders here in the U.S. And the primary way doctors diagnose patients with depression is by interviewing them. But scientists at Northwestern University this past week announced they had developed a blood test that could diagnose the disease. Doctor David Mohr is the co-author of that study. We discussed how these findings could potentially change the way doctors treat mental illness.

DAVID MOHR: Our ability to diagnose depression currently is based entirely on nonspecific symptoms like poor mood and fatigue and changes in appetite and changes in sleep. And these are common in lots and lots of other mental health problems, as well as medical problems. So without something that is very very specific, it makes the job of a physician with very limited time very difficult.

You know, the state of diagnosis in psychiatry right now, I think, is kind of where medicine was 100 years ago. Then, you had yellow fever and scarlet fever and black fever. You know, with the advent of laboratory tests, they were able to much more clearly and much more quickly diagnose problems and then identify treatments that would likely treat those.

RATH: So can you explain what a test like this actually tells us?

MOHR: One of the things that we looked at was trying to identify, using biomarkers, people who were experiencing a major depression from people who were not - you know, markers that might be able to predict response to treatment - so those who got better versus those who didn't, as well as identifying people who were at risk for depression at the end, even though they might effectively treated.

RATH: So that even if you've had a successful treatment for depression, you would still have those markers in some way?

MOHR: Right. And I think that's an important piece. Because it's a relapsing remitting disorder, being able to identify those people who are at risk can allow clinicians to identify those people who need to be followed more closely to try to catch a relapse of major depression early and treat it early.

RATH: Do you think that having a test like this then could help the problem of people that avoid treatment because of the stigma?

MOHR: Well, I think it helps with the first step. So if a depression can be effectively treated in primary care, then there's no reason to refer them to mental health professionals. You know, a good portion of patients will respond to antidepressant medications prescribed properly by primary care physicians. But there also will be a good number of patients who don't necessarily respond to those treatments and they will need a referral.

RATH: On the question of reliabilities - say this is correct 95 percent of the time - what about the people that it misses and the danger of say insurance saying well, the test says you don't have depression, so no treatment for you?

MOHR: We can talk about this study specifically. And I think I wouldn't want to see this implemented now based on this one finding with a relatively small number of patients. So whether these tests are valid and how reliable they are, I think is something that needs to be investigated. But to your point, no test is perfect.

RATH: Doctor David Mohr, thank you.

MOHR: It's been a pleasure.

Copyright © 2014 NPR. All rights reserved. Visit our website terms of use and permissions pages at for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.