Depression harms more than just the mind: research has linked the ailment with a host of physical conditions, including type 2 diabetes, heart disease, and cancer. Now, fascinating new research suggests that depression might also accelerate the aging process at a cellular level.

In a study published this week in Molecular Psychiatry, investigators out of the Netherlands used the length of telomeres — essentially protective caps at the ends of chromosomes that shorten every time a cell divides — in an effort to determine the impact of depression on the biological aging process. The length of telomeres has long been considered a marker of a cell's age, and older people and animals have been shown to have shorter telomeres.

Patients with a history of depression had shorter telomeres

This latest study divided more than 2,000 adult participants into three groups: those who'd been previously diagnosed with a major depressive disorder, those currently struggling with the condition, or those who'd never been depressed. Even after controlling for factors like smoking, nutrition, alcohol consumption, and weight, the team found that patients with a history of depression had shorter telomeres than their peers. Those who'd suffered from more severe depression, or chronic symptoms, exhibited the most significant reduction in telomere length.

More specifically, participants with depression had an average telomere length of 5,460 bp (base pairs) compared to an average of 5,540 bp for healthy participants. Telomeres typically shorten by between 14 and 20 bp per year, earlier research has indicated. "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," study leader Josine Verhoeven told Live Science. "The findings might help explain the variety of health complaints often experienced by people with major depression."

"A large, detrimental impact on the 'wear and tear' of a person's body."

It's important to note that this single study merely found an association between depression and telomere length, and that future research will be key to validating and unraveling that relationship. Depression might trigger damage at a cellular level, or shorter telomeres might contribute to depression risk. It's also possible that some unknown genetic factor explains both phenomena. Plus, telomere shortness hasn't been robustly linked to a shorter lifespan — so it's unclear whether shorter telomeres, at least alone, are clinically relevant.