In 1965 cell biologists reported a thought-provoking discovery—the
older a person, the fewer times his or her cells divide when cultured in the
In 1990, cell biologists reported something even more
interesting—each time a human cell divides in lab culture, the length of
the telomeres (DNA-protein complexes) capping the ends of its chromosomes
shortens a bit, until the point at which the telomeres become so short that
the cell is unable to divide further. The cell then dies.
Thus, cell aging appears to be related to the normal chronological aging
process and under the control of telomeres. Telomere shortening might be
viewed as a cell clock that ultimately controls the number of cell divisions
and cell life span.
But the story doesn't stop there. Enter psychiatry....
In 2004 Elissa Epel, Ph.D., an assistant professor of psychiatry at the
University of California, San Francisco, and colleagues reported that women
psychologically stressed by caring for a chronically ill child had shorter
telomeres than did same-aged women without such a burden. So psychological
stress may well hasten the normal telomere shortening process, Epel and her
group concluded (Psychiatric News, January 7, 2005).
And now Naomi Simon, M.D., associate director of Massachusetts General
Hospital's Center for Anxiety and Traumatic Stress Disorders, and coworkers
have found in a pilot study that individuals with mood disorders have shorter
telomeres than do healthy control subjects. Their findings are in press with
Simon and her colleagues suspected that the psychological stress associated
with mood disorders might accelerate cell aging. They decided to assess
whether individuals with mood disorders have abnormally short telomeres, a
hallmark of hastened cell aging. They recruited 88 subjects, 44 of whom had
one or more DSM-IV mood disorders (15 had major depressive disorder,
14 bipolar disorder, and 15 bipolar disorder plus anxiety).
The other 44 were age-, gender-, and ethnicity-matched mentally healthy
controls. White blood cells were taken from each subject and assessed for
Telomere length for the three groups with a mood disorder was virtually the
same, the researchers found. However, when the telomere lengths of all three
groups were combined and compared with the telomere length of the control
group, the former were significantly shorter (see chart).
In fact, individuals with mood disorders were found to have such truncated
telomeres that they represented 10 years or more of accelerated aging, the
"The finding of shorter telomere length in patients with mood
disorders compared with controls, potentially representing 10 years or more of
accelerated aging, was what we expected," Simon told Psychiatric
News. "However, we also expected to see even greater relative
telomere shortening in individuals with both a mood disorder plus an anxiety
disorder; we did not find this, but it may be due to the limitations of this
initial pilot study."
Despite possible limitations, "Our study is the first to demonstrate
accelerated telomere shortening in mood disorders, or in any chronic
psychiatric disorder," Simon and colleagues wrote, "and suggests
that chronic mood disorders contribute to acceleration of aging
"The current findings by Simon and colleagues extend our finding
linking perceptions of life stress to telomere shortening, to the realm of
psychiatric disorders, mainly depression," Epel told Psychiatric
News. "This is a solid study that demonstrates the finding that
many in the field have long suspected—that depression is
The results also suggest that if depression, or the psychological stress it
imposes, can truly hasten telomere shortening, then that accelerated
shortening might make people prematurely susceptible to medical diseases that
tend to occur as people grow older. Indeed, there is evidence pointing in that
For example, Epel and her group recently found that in healthy young and
middle-aged subjects, a significant link exists between elevated levels of
stress hormones and shorter telomere length. In another investigation,
middle-aged subjects who had had heart attacks were found to possess telomeres
that were significantly shorter than those of healthy control subjects.
Similar results emerged from another study of subjects (average age 61)
with type II diabetes. Accelerated telomere attrition has even been linked to
increased rates of cancer in experimental animals.
Finally, if future studies can confirm that mood-disorder-provoked telomere
shortening can indeed trigger medical diseases, then it might also reveal
novel pathways for treating or preventing these diseases, Simon and her group
The current study was funded by the National Institute of Mental Health,
National Institute on Aging, Massachusetts General Hospital, and the Flight
Attendant Medical Research Institute. Simon and her team have received funding
from the National Alliance for Research on Schizophrenia and Depression to
study telomere length further in subjects who have either bipolar disorder or
bipolar disorder plus an anxiety disorder.
An abstract of "Telomere Shortening and Mood Disorders:
Preliminary Support for a Chronic Stress Model of Accelerated Aging" can
be accessed from<www.journals.elsevierhealth.com/periodicals/bps/home>.▪