A group of scientists led by Professor Alexander B. Niculescu from Indiana University School of Medicine has developed an RNA biomarker blood test that can detect the severity of a patient's depression, as well as informing on the risk of a patient developing severe depression or bipolar disorder in the future.
The latest blood test built on previous work by Niculescu's group where they identified blood biomarkers that could track suicidality and post-traumatic stress disorder. The description of their latest blood test for depression and bipolar disorder is published in the journal Molecular Psychiatry.
“We have pioneered the area of precision medicine in psychiatry over the last two decades, particularly over the last 10 years. This study represents a current state-of-the-art outcome of our efforts,” said Niculescu. “This is part of our effort to bring psychiatry from the 19th century into the 21st century. To help it become like other contemporary fields such as oncology. Ultimately, the mission is to save and improve lives.”
Developing the test took considerable work. Spanning 4 years and involving more than 300 participants, Niculescu's team procedurally followed a four-step plan to uncover which biomarkers were going to be important to developing a blood test for depression and bipolar. Firstly, they followed a group of participants in the study over a period of time, assessing changes in their mood – up or down – and correlating that with biomarker changes that occurred in their blood going from one mood to the other.
After identifying some candidate biomarkers that changed levels with mood changes, Niculescu's team then cross-referenced and validated the biomarkers they had picked up on with all previously documented biomarkers from related studies in the field. They identified 26 key biomarkers which they then used in a follow-up investigation where they tracked the changes of these biomarkers in a cohort of patients that had clinically severe depression or mania. Following that validation, they then used the biomarkers in a different cohort of patients to test how well they could use the markers to assess how ill a patient might be or might become in the future.
Thereafter, based on their findings and the ability of the biomarker blood test to accurately assess patient outcomes, they then used it to tailor medication to patient needs.
“Through this work, we wanted to develop blood tests for depression and for bipolar disorder, to distinguish between the two, and to match people to the right treatments,” said Niculescu. “Blood biomarkers are emerging as important tools in disorders where subjective self-report by an individual, or a clinical impression of a health care professional, are not always reliable. These blood tests can open the door to precise, personalized matching with medications, and objective monitoring of response to treatment.”
Interestingly, during their study, the Niculescu team also uncovered another important link between circadian rhythm genes – the genes that regulate our internal day-night clock, wakefulness, and seasonal changes – and mood disorders. This might explain why some patients get more severe symptoms when seasons change, as well as the sleep disturbances often reported in mood disorders.
In an era where blood biomarkers are increasingly used in medicine to assess and diagnose, this study adds an important step forward in getting a viable blood test for depression and bipolar into the clinic.
“Blood biomarkers offer real-world clinical practice advantages. The brain cannot be easily biopsied in live individuals, so we’ve worked hard over the years to identify blood biomarkers for neuropsychiatric disorders,” Niculescu concludes. “Given the fact that 1 in 4 people will have a clinical mood disorder episode in their lifetime, the need for and importance of efforts such as ours cannot be overstated.”
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