New Blood Test Could Diagnose Depression

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Lisa Winter

Guest Author

829 New Blood Test Could Diagnose Depression
Vincent van Gogh

Everyone goes through hard times every now and again, but for as many as 1 in 10 American adults, it is much more than just occasionally getting the blues. Clinical depression is a very real and serious mood disorder in which the person has relentless negative feelings that can’t be easily shaken off or overcome. A correct diagnosis and treatment can significantly improve quality of life. A new study indicates that biomarkers in the blood may be useful in the future for diagnosing depression. The research was performed by a team led by Lukas Pezawas of the Medical University of Vienna and the results were published in PLOS ONE.

Serotonin is a molecule with an impressive host of functions, but it is usually regarded as a mood regulator and is colloquially called the ‘happiness hormone’. Low serotonin levels are often linked to depression. Serotonin transporter (SERT) proteins ensure that the flow of serotonin gets to where it needs to go in the cells. Sometimes the SERTs will reabsorb the serotonin, which sort of acts like clogged drain, as the signal is not able to move on to the next neuron. When a person is diagnosed with depression, their physician may try to target SERTs by prescribing selective serotonin reuptake inhibitors (SSRIs) which prevents a cell from reabsorbing the serotonin, forcing the signal to move on as intended. The hope is that SSRIs regulate the flow of serotonin in the body and improves hormonal balance, and so improves mood.


The researchers used functional MRI (fMRI) to determine how readily serotonin was taken up by the cells in the blood and how it related to the depression neural network. They found a very strong correlation between the two, which could mean that monitoring levels of serotonin in the blood could eventually be used as a diagnostic tool.

This study is incredibly exciting, because it is the first time it has been shown that a blood test could be capable of diagnosing depression; a fact that physicians have long lamented did not seem possible. What’s better, Pezawas said in a press release that this “could become reality in the not too distant future.” Diagnosing on a biological basis may also help ensure that the patient is getting properly dosed to create the best possible outcome. 


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  • blood test,

  • depression,

  • serotonin,

  • ssri,

  • sert,

  • biomarkers