Researchers Develop Blood Test That Could Detect Depression Before Symptoms

Depression may soon be detected not just through words, but through cells quietly aging in the bloodstream. New research suggests that patterns in immune cell aging could offer a biological clue to diagnosing Depression, particularly its emotional and cognitive symptoms.

Published in The Journals of Gerontology Series A, the article explores how biological aging, measured through “epigenetic clocks,"-relates to mental health. Unlike traditional diagnosis, which relies heavily on patient-reported symptoms, this approach looks at measurable changes in DNA chemistry over time.

The researchers focused on monocytes, a type of white blood cell involved in immune defense. They found that accelerated aging in these cells was strongly linked to non-physical symptoms of depression, such as hopelessness, loss of pleasure (anhedonia), and cognitive difficulties. Interestingly, this connection appeared in both women living with HIV and those without it.

This distinction matters. In many cases—especially among people with chronic illnesses like HIV—physical symptoms such as fatigue are often attributed to the underlying disease rather than depression. By contrast, this study highlights a biological signal tied specifically to emotional and cognitive distress, potentially helping clinicians identify depression more accurately.

The study analyzed 440 women from the Women’s Interagency HIV Study, combining psychological assessments with blood-based measurements of biological age. While a general epigenetic aging measure showed no clear link to depression, the monocyte-specific clock stood out as a potential marker.

Researchers caution that more studies are needed before such tests become routine. Still, the work represents a significant step toward “precision mental health,” where biology and lived experience come together to guide care more effectively.

REFERENCE: Nicole Beaulieu Perez, Ke Xu, Yanxun Xu, Lang Lang, Kathryn Anastos, Maria L Alcaide, Mardge Cohen, Sadeep Shrestha, Andrew Edmonds, Jacquelyn Meyers, Seble Kassaye, Igho Ofotokun, Gypsyamber D’Souza, Bradley Aouizerat, Leah H Rubin. Monocyte Epigenetic Age Acceleration is Linked to Non-Somatic Depressive Symptoms in Women with and Without HIV. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 2026; DOI: 10.1093/gerona/glag083