Screening for depression might soon be as easy as a blood test.
A new test that identifies particular molecules in the blood could help doctors diagnose patients with clinical depression, according to a new study published in the journal Translational Psychiatry. The blood test can also predict which therapies would be most successful for patients, and lays the groundwork for one day identifying people who are especially vulnerable to depression–even before they've gone through a depressive episode.
But perhaps just as important, said lead investigator Eva Redei, PhD, is the potential the test has for taking some of the stigma out of a depression diagnosis. When depression can be confirmed with a blood test like any other physical ailment, she said, there's less stigma about having the disease and getting treatment.
"I really believe that having an objective diagnosis will decrease stigma," Redei, a neuroscientist and professor at the Northwestern University Feinberg School of Medicine, told The Huffington Post.
"Once you have numbers in your hand, you can identify that (depression) is an illness–not a matter of will."
The most effective way to treat depression is to treat it early, but past studies show that it takes an average of two to 40 months to diagnose depression–if it gets diagnosed at all. Redei's depression blood test could lead to faster and more accurate diagnoses, thereby transforming the way depression is treated.
If Redei's findings are independently replicated and confirmed, then approved by the Food and Drug Administration, laboratories across the US could incorporate the test into their battery of routine exams.
This is in contrast to MDDScore, a depression blood test owned by Ridge Diagnostics that was announced in 2012. Because the test is proprietary to Ridge Diagnostics, doctors have to submit samples to the company's lab in North Carolina, where the company analyses the blood and sends back results. Redei's test, however, "can be done by any clinical laboratory anywhere, just like a cholesterol test," Redei explained.
"That is, assuming that we can go through the FDA approval (process) fast."
Redei's study compared the blood samples of 32 patients who had been diagnosed with depression in the traditional way (a clinical interview) with samples taken from 32 people without depression. She found nine RNA blood markers–the molecules that carry out DNA's instructions–that differed significantly between the two groups, which she then used as the basis for the depression diagnosis.
Then, the depressed patients went through 18 weeks of cognitive behavioural therapy, a common treatment for depression. Re-testing their blood, Redei was able to tell which patients had benefitted the most from therapy, just by examining the changes in their RNA markers. In other words, the test was also a biological way to tell if treatment had been effective.
Finally, Redei also noticed that there were three RNA markers that didn't change in depressed patients, no matter if they had benefitted from cognitive behavioural therapy or not. She suspects they may be markers that show if a person is predisposed to depression.
"Being aware of people who are more susceptible to recurring depression allows us to monitor them more closely," said David Mohr, PhD, co-lead author of the study in a press release.
"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." (Huffington Post)