A new study has found that a marker of biological aging, measured through blood tests, is associated with some but not all symptoms of depression. The research, published in the journal Nature Communications on May 11, 2026, focused on epigenetic clocks that track the aging of certain white blood cells.
Scientists from the University of California, San Francisco, analyzed data from over 2,500 adults aged 50 and older. They found that accelerated aging of immune cells, specifically CD4+ T cells, was linked to cognitive and mood-related symptoms of depression, such as difficulty concentrating and feelings of sadness. However, this marker was not associated with physical symptoms like fatigue or sleep disturbances.
βOur findings suggest that biological aging may specifically affect the brain-based symptoms of depression,β said Dr. Elissa Epel, lead author of the study. βThis could help identify individuals at higher risk for these symptoms and lead to targeted interventions.β The researchers used a blood test that measures DNA methylation patterns to calculate the epigenetic age of immune cells.
The study controlled for factors like age, sex, and chronic health conditions. The link remained significant even after adjusting for these variables. The authors caution that the findings are observational and do not prove causation, but they open new avenues for understanding the connection between aging and mental health.
