The Surprising Way Depression Can Alter Your Immune System

We know that depression can impact our lives in a number of ways, from finding the motivation to get out of bed in the mornings to feeling confident enough to interact with peers. But new research is showing that not only can depression cause lifestyle changes it can cause physiological changes as well, altering the actual cells in your body.

Depression is common in U.S. adults — 8.4% of the population had at least one depressive episode in 2020, according to the National Alliance on Mental Illness (NAMI). Contributing factors include childhood trauma, genetics, environmental stressors, substance abuse, and other medical conditions like chronic pain. Episodes can last two weeks to several years but can be managed with treatment. Treatment options include psychotherapy, medication, physical activity, and brain stimulation therapies. If major depressive disorder, or an episode that lasts at least two weeks, goes untreated, it can become persistent depressive disorder, which lasts more than two years and can affect you for a lifetime (via Medical News Today).

A new study published in Translational Psychiatry has found a connection between persistent depressive disorder and changes in blood cells and immune cells. Researchers analyzed data from 69 participants at high risk for depressive disorders, as well as 70 healthy participants. Mental health conditions were evaluated using a globally-recognized interview process. Over 16 million blood cell images were then scanned, measuring cell size, the cells' ability to change shape, and their ability to exhibit deformability. Researchers found that in those with persistent depressive disorder over their lifetime, immune cells were more likely to be deformable. They weren't as able to maintain shape and internal organization, which affected function and could potentially lead to other medical conditions.

We know that depression can cause chronic inflammation and an increase in stress hormones (via Medical News Today). However, it's not clear if these effects lead to deforming of the immune cells or the other way around. While more research is needed, this study is important for delineating the biological impact of depression and paving the way for future studies. Dr. Andreas Walther, lead author of the study, feels that this research is necessary for advancing more efficient and sustainable treatments for depression in the long term (via Medical News Today).