A new study, performed by researchers from the Netherlands, has tentatively linked individuals experiencing depression to faster aging. The group goes as far as to suggest that depression could accelerate the aging process by a number of years.
The findings were published in the journal Molecular Psychiatry on Nov. 12, and explored the potential impact that major depressive disorders conferred on the length of small structures called telomeres, which serve as the protective caps at the end of each chromatid.
The telomeres help to defend the chromosome during cellular division, preventing fusion of adjacent chromosomes and impeding deterioration of genes located at the ends of chromosomes. Since the ends of chromosomes shorten during cellular replication, the telomeres allow this process to occur without losing essential genetic information. As such, the telomeres comprise a repetitive series of nucleotide sequences and, through their service as buffers, become shorter themselves.
The study investigated 1,900 participants who had experienced serious depressive disorders, at some point in their lives, and contrasted their telomere lengths to 500 individuals who had never been afflicted with any form of depressive disorder.
Previous studies have formed tentative relationships between telomere lengths and aging, with many equivocally suggesting them to be cellular markers of age. Telomere length has also be linked to a number of pathologies, including aplastic anemia, cancer, dyskeratosis congenita and pulmonary fibrosis, and are known to serve a role in DNA damage responses and cellular fitness.
During certain pathologies where telomeres are unable to function appropriately, as witnessed in Werner syndrome, sufferers experience rapid aging. Werner syndrome was first identified by German scientists Otto Werner, whilst investigating four siblings. It was established that the premature aging was sometimes associated with missing telomeres, resulting in some chromosomes becoming stuck together; ultimately, Werner sufferers experienced premature aging within their 20s and often died from cardiovascular disease and cancer.
Depression Could be Linked to Telomere Length
The research team found some intriguing results. Those individuals who had previously suffered depression had shorter telomere lengths compared with the control group, who had no history of depression. Based upon their results, the team speculated that depression could accelerate the aging process by a number of years.
The intensity and duration of a sufferer’s depression also appeared to correlate with telomere length. Symptoms that manifested over a protracted period, alongside high severity of depression, were both linked to a shortening in telomere length. A number of additional factors that were deemed capable of contributing towards aging, were also taken into consideration, including alcohol consumption, smoking and weight; regardless of the afore-mentioned lifestyle choices, depression was consistently linked to a reduction in telomere length.
The research study author Josine Verhoeven, based at the Free University in Amsterdam, briefly ruminated over the impact of psychological mindset on the acceleration of the aging process.
“Psychological distress, as experienced by depressed persons, has a large, detrimental impact on the ‘wear and tear’ of a person’s body, resulting in accelerated biological aging… The findings might help explain the variety of health complaints often experienced by people with major depression”
The participants included a diverse age group, ranging from 18 through to 65. The results of Verhoeven and colleagues corroborated previous research, finding that, for each year added to a participant’s life, the telomere length would shorten by an average of 14 base pairs.
The study determined that healthy people had an average telomere length of 5,540 base pairs, whereas the group that comprised of people that had a history of depression had an average telomere length of 5,460 base pairs. Each base pair represents a single complementary pair of nucleotides, which represent the building blocks of DNA.
Although the research findings seemed to show a link between depression and altered telomere length, the study authors remain cautious in interpreting their results. They suggest that other factors could contribute towards the phenomenon, such as genetic susceptibility or dysfunction in the body’s ability to tolerate certain stressors.
Meanwhile, Verhoeven ruminates over whether the aging process can somehow be reversed. She suggests that lifestyle changes could play a crucial role.
Indeed, a recent study led by Dean Ornish of the Preventative Medicine Research Institute at the University of California, San Francisco, found a possible relationship between lifestyle and telomere length. After recruiting subjects between 2003 and 2007, the research team created two groups; one group had to adhere to a strict regimen, involving regular exercise, healthy eating and social support, whereas the other group was used as a simple control.
Blood samples were obtained five years after the study commenced and telomere length and telomerase enzyme activity were measured. Telomerase is an enzyme that adds DNA sequence repeats to the terminus of telomere regions, and its activity is often found to decline with age; some researchers have even posited that telomerase could be used as a clinical therapy against aging, but opinion within the scientific community remains mixed.
The “healthy” group demonstrated a slower decline in telomere length, relative to the controls; however, telomerase activity continued to decline in both sets of participants, suggesting that lifestyle factors may not necessarily play a major part in the enzyme’s activity.
Ultimately, it remains debatable as to whether depression is indisputably related to telomere length and the aging process. However, with telomere research becoming an increasingly desirable source of study, it seems we are destined to know more over the coming years.
By James Fenner