Emerging research suggests depression may do more than just affect one’s mental health.
University of California-San Franciso researchers report that in certain cases, depression causes premature aging of immune cells, an event which may predispose individuals to certain types of chronic illness.
“There’s a lot more to depression than feeling blue,” said lead author Owen Wolkowitz, M.D., a professor of psychiatry at UCSF. “As if feeling depressed is not bad enough, we are finding that long-term depression may be associated with damage to cells in the body, and this may predispose patients to certain physical diseases.”
Researchers say accelerated cell aging does not occur in all depressed individuals, but is dependent upon how long someone is depressed, particularly if that depression goes untreated.
Researchers now believe major depressive disorder may shorten the telomeres — sections of repetitive DNA at the ends of chromosomes — in immune cells, leading to premature aging. As a consequence, depressed individuals could be at a higher risk of developing diabetes, heart disease, osteoporosis, stroke and dementia.
The study was published online in the journal PLoS One.
Telomeres seal off and protect the ends of chromosomes and act as a biological clock controlling a cell’s life. Telomere shortening predicts earlier onset of several major age-related diseases and earlier mortality, and may serve as one index of human longevity.
In the study, the length of telomeres in 18 individuals presenting a diagnosis of major depressive disorder and not receiving antidepressant medications were compared to the telomere length in 17 healthy individuals.
Overall, telomeres of the depressed group did not differ from those of the healthy group; however, individuals with nine or more years of untreated chronic depression showed significant telomere shortening, even after accounting for chronological age.
The degree of shortening in this subset of the depressed group corresponded to about seven years of “accelerated cell aging.”
Cell inflammation and oxidative stress are often linked to telomere shortening – a characteristic of cell damage and premature aging. Oxidative stress has received considerable attention as a perpetrator of ill health, with the condition linked to an imbalance between the destructive molecules known as free radicals, and antioxidants.
In this study, the authors suggest that telomere shortening in very chronic depression may reflect an individual’s cumulative exposure to biochemical stressors that promote cell death and increase the likelihood of physical disease.
“While this finding itself might seem depressing, there is yet good news: Many lifestyle factors like exercise and aspects of diet have been linked to longer telomeres,” said co-author Elissa Epel, Ph.D., an associate professor in the UCSF Department of Psychiatry.
“So while our personal history matters, it is possible that what we do today may matter even more, in terms of protecting our telomeres.”