Depression can shorten your telomeres

A meta-analysis published this year in the Journal of Affective Disorders has demonstrated a substantial link between depression and telomere length. Because telomere degradation is correlated with a shorter lifespan, this new research provides a possible biological answer as to why people with depression tend to have higher mortality rates: the prolonged stress of depression may shorten its sufferers’ telomeres and, in turn, their lives.

Researchers applied statistical tests to 38 extant studies of individuals with and without Major Depressive Disorder that had measured those individuals’ telomere lengths. The meta-analysis found that subjects with a depression diagnosis tended to have shorter telomeres than their non-depressed peers, at a statistically significant rate.

In the past, individual studies of depression and telomere length have borne inconsistent outcomes, potentially due to their small sample sizes. However, the results of this new meta-analysis are more conclusive.

These results both corroborate and go beyond a previous meta-analysis of similar data, published in 2015, that also found a negative association between depression and telomere length. However, the more recent meta-analysis has expanded the dataset of the previous study by 39%, and has also taken into account new factors that could affect patients’ telomere length, such as: the severity and length of their depression; comorbid conditions; smoking; and the tissue source from which the telomeres were drawn. Of these factors, the second meta-analysis found that only the severity of patients’ depression seemed to influence their telomere length, suggesting that the link between telomere length and depression cannot, for instance, be dismissed merely as an effect of higher smoking rates among depressed patients.

This meta-analysis adds depression to the long list of disorders and diseases that are correlated with shorter telomeres, from cardiovascular disease to cancer. The study opens the door for future research into whether the relationship between telomere shortening and depression is indeed causal, and where, on the timeline of depression, telomere shortening begins. Telomere length may someday be of use to physicians as a metric for the severity, and best course of treatment, of a patient’s depression.