A new study suggests that biological aging of certain immune cells could serve as a biomarker for depression, offering a potential new way to diagnose the mood disorder beyond self-reported symptoms.
Researchers published their findings in The Journals of Gerontology. The study examined the relationship between biological aging and depression, focusing on a sample of women with and without HIV. Because depression is more common among people with autoimmune conditions, the researchers used HIV as a model for immunodeficiency.
The study included 261 women with HIV and 179 without, all participants in the Women’s Interagency HIV Study. Researchers measured depression levels using the Center for Epidemiologic Studies Depression Scale (CES-D). Blood tests were taken to assess the biological aging of white blood cells.
The analysis focused on monocytes, a type of white blood cell. The study authors noted that monocytes play a large role in HIV infection and are often elevated in people with depression. The results showed that monocyte aging was a biomarker for non-somatic depression symptoms, such as hopelessness, loss of joy, and feelings of failure. This finding held true for women both with and without HIV.
Study co-author Nicole Beaulieu Perez, Ph.D., explained in a news release that people with HIV often have physical symptoms like fatigue that are attributed to their chronic illness rather than to depression. “But this flips that on its head because we found that these measures are associated with mood and cognitive symptoms, not somatic symptoms,” Beaulieu Perez said.
Identifying a biological marker for mood disorders could change how depression is diagnosed. Currently, depression is almost always diagnosed based on self-reported symptoms. “Depression is not a one-size-fits-all disorder—it can look really different from person to person, which is why it’s so important to consider varied presentations and not just a clinical label,” Beaulieu Perez said. “Our study reveals unique biological underpinnings of mental health that are often obscured by broad diagnostic categories.”
The study authors noted that more research is needed to understand the connection between biological aging and mood disorders. However, the findings show promise for future diagnostic and treatment pathways. “I think about the adage, ‘What gets measured gets managed.’ An aspirational goal in mental health would be to combine subjective experience with objective biological testing,” Beaulieu Perez said.
Depression and other mood disorders take a major toll on those affected, making both diagnosis and treatment critical. This study points to a new way of understanding the connection between the body and mind, and potentially new ways to work with that connection. “Our findings bring us a step closer to this goal of precision mental health care, especially for high-risk populations, by providing a biological framework that could guide future diagnosis and treatment,” Beaulieu Perez said.
