It has long been known that stress can be manifested by outward signs of aging and can also produce numerous damaging effects on the human body, and latest findings have revealed that depression, may also accelerate the aging process. 

Scientists have revealed that protective caps on the ends of chromosomes called telomeres, which shorten as people age, shrink more rapidly in times of stress and depression. 

Researchers explained that the human stress response is controlled by the hypothalamic-pituitary-adrenal (HPA) axis that controls the body’s primary stress hormone called cortisol, and significant abnormal HPA axis function were exhibited in individuals with depression- and stress-related illnesses.

The new study examined the relationships between telomere length, stress, and depression in 542 participants, 91 of those were affected with recurrent major depressive disorder by measuring telomere length in depressed healthy individuals.

Researchers also measured stress levels by measuring cortisol levels and through participant questionnaires.

Researchers confirmed that telomere length was far shorter in the depressed patients, and also discovered that shorter telomere length associated with low cortisol states in both the depressed and healthy groups.

"Our findings suggest that stress plays an important role in depression, as telomere length was especially shortened in patients exhibiting an overly sensitive HPA axis. This HPA axis response is something which has been linked to chronic stress and with poor ability to cope with stress," lead author Dr. Mikael Wikgren explained in a statement released on Tuesday.

"The link between stress and telomere shortening is growing stronger. The current findings suggest that cortisol levels may be a contributor to this process, but it is not yet clear whether telomere length has significance beyond that of a biomarker," commented Dr. John Krystal, editor of Biological Psychiatry in which the findings were published this week.

Just as telomere shortening has been linked to aging, researchers had previously posited that lengthening the telomeres in certain cells could promote extend life and reverse aging. 

Currently, the theory had not been tested on humans, but Harvard researchers have demonstrated that telomere extension has successfully reversed some signs of aging in laboratory mice and in an experiment, published in the journal Nature in November 2010, where researchers revitalized worn out organs in elderly mice, dramatically reversed the aging process by injecting mice with the enzyme called telomerase that stopped their telomeres from getting shorter.

Last month Medical Daily reported that about one in five American adults, or nearly 50 million people, have suffered mental illnesses in 2011, according to the latest government report released last month.

Substance Abuse and Mental Health Services Administration had defined mental illness among adults aged 18 or older as diagnosable mental, behavioral or emotional disorders, based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders and excluded developmental or substance use.

SAMHSA had conducted a survey had also found that that five percent of Americans or 11.4 million people were affected with a serious mental illness in the past year that significantly interfered with their lives.

Around 8.7 million American adults had serious thoughts of suicide in 2011, including 2.5 million making suicide plans and 1.1 million attempting suicide, according to SAMHSA.

“Mental illness is a significant public health problem in itself, but also because it is associated with chronic medical diseases such as cardiovascular disease, diabetes, obesity, and cancer, as well as several risk behaviors including physical inactivity, smoking, excessive drinking, and insufficient sleep,” Ileana Arias, Principal Deputy Director of the Centers for Disease Control and Prevention, had said in a statement released in January.

Researchers in the latest study noted that future research on determining whether controlling telomere length could be used as a component of the treatment process of depression or stress is needed to improve the understanding mental illness and hypo-cortisolism and their effects on premature telomere shortening and health.