Monocyte Aging Blood Test Shows Promise for Early Depression Detection in New Biomarker Study

Researchers at New York University published a study May 4, 2026, in *The Journals of Gerontology, Series A* examining 440 women, including those with and without HIV, to explore links between monocyte aging and depression. They found that accelerated biological aging of monocytes was associated with non-somatic depression symptoms such as hopelessness and anhedonia, suggesting monocyte aging could serve as a biomarker for early detection of mood-related depression, according to the study.

These findings were based on analyses of blood samples using epigenetic clocks, specifically the MonoDNAmAge clock, which estimates biological age of monocytes through DNA methylation patterns, according to lead researcher Nicole Perez, PhD, of New York University.

The study found that accelerated biological aging of monocytes, a type of immune cell, was significantly associated with higher total depression scores, driven primarily by non-somatic symptoms such as anhedonia, hopelessness, feelings of failure, and sleep disturbances.

Perez and her team reported that the association between monocyte aging and depression symptoms was specific to non-somatic, or mood-related, symptoms and showed no significant link to somatic symptoms such as fatigue or appetite changes, which are often present in depression but can overlap with physical illness symptoms. The study’s results held true in the overall sample of 440 women, which included 261 women living with HIV and 179 without HIV, although some subgroup analyses within the HIV-positive group did not reach statistical significance.

The research also utilized the Horvath epigenetic clock, a multi-tissue biological aging measure, but found no significant associations between Horvath clock estimates and either somatic or non-somatic depression symptoms. This distinction underscores the potential of monocyte-specific aging markers as more precise indicators of mood-related depression, according to the study published May 4, 2026, in *The Journals of Gerontology, Series A*.

The participants were drawn from the Women’s Interagency HIV Study (WIHS) cohort, a long-standing observational study focused on women with and without HIV. The inclusion of women living with HIV was particularly relevant because, as Perez noted, physical symptoms like fatigue in this population are often attributed to chronic illness rather than depression, complicating diagnosis. “This is particularly interesting because people with HIV often have physical symptoms like fatigue that are attributed to their chronic illness rather than a depression diagnosis,” Perez said in a statement.

Depression symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D), which allowed researchers to differentiate somatic symptoms from non-somatic symptoms. The study emphasized that total depression scores from tools like the CES-D can mask underlying biological differences, highlighting the need for multidimensional measurement approaches in clinical research and care, Perez said.

The study’s methodology involved analyzing DNA methylation patterns in blood samples to estimate biological age. The MonoDNAmAge clock focuses specifically on monocytes, which play a key role in immune response and are implicated in HIV infection. The researchers found that monocyte aging tracked emotional and cognitive symptoms of depression more closely than physical symptoms, supporting its potential use as a biomarker for early detection of mood-related depression.

While the overall findings were statistically significant, subgroup analyses within women living with HIV showed similar patterns but did not always meet significance thresholds, likely due to smaller sample sizes. Perez noted that the study controlled for other possible contributors to depression symptoms, such as hypothyroidism or anemia, to isolate the effects related to monocyte aging.

The research offers a potential pathway toward a simple blood test that could identify depression early, before full clinical symptoms develop. This could be especially valuable in populations where somatic symptoms overlap with chronic illness, such as women living with HIV. The study’s authors emphasized that further validation is needed before clinical application.

The findings build on prior research linking monocyte epigenetic age acceleration to mood disorders, as highlighted by Perez in a recent YouTube interview. The study contributes to ongoing efforts to identify objective biomarkers for depression, a mood disorder affecting nearly one in five adults in the United States.

Published on May 4, 2026, the study advances understanding of the biological underpinnings of depression and points to monocyte aging as a promising target for future research. Further studies are necessary to confirm these results and explore their clinical utility across diverse populations.