Interesting news in the mental health world: Researchers at Northwestern University have developed an early version of a blood test designed to diagnose depression. They tested the assay and reported the results this week in a study in Translational Psychiatry.

The researchers recruited 32 patients who had been diagnosed with depression using a standard clinical evaluation, as well as 32 non-depressed patients to act as a control. The researchers then took blood samples from each subject and submitted them to a test of nine biomarkers of depression. Not only were the researchers able to suss out which patients had depression based solely on the blood tests, they were also able to track the ways in which the biomarkers changed over the course of 18 weeks of cognitive behavioral therapy.

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Depression isn’t that hard to diagnose, experts say—clinical evaluations are fairly standardized, fast and easy—but this is the first blood test for any type of mental disorder in adults, according to the study co-author. That means it’s the first time we’ve had an objective gauge of mental health—as well as a measure of how well treatments are working.

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The test is still in the early stages, but you can bet we’ll be following this news as it develops.

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