Long-term depression may ultimately double the risk of stroke among middle-aged adults, according to a new study out of Harvard T.H. Chan School of Public Health. Particularly among adults over the age of 50, depressive symptoms that are persistent over time can ultimately have a negative effect on health.

The study follows on the heels of a 2013 paper that discovered middle-aged women had an almost double risk of stroke due to depression. Even after eliminating risk factors such as age, socioeconomic status, lifestyle habits like smoking, alcohol, and physical activity, depressed women were still more likely to have a stroke. Another recent study found that two-thirds of stroke survivors experience depression and anxiety after leaving the hospital, which implies the depression-stroke link may be a vicious cycle.

Ultimately, researchers believe this accumulating evidence is just more reason to put greater emphasis on treating mental illness in the health care system.

“This is the first study evaluating how changes in depressive symptoms predict changes in stroke risk,” Paola Gilsanz, an author of the study and a Yerby Postdoctoral Research Fellow at Harvard Chan School, said in the press release. “If replicated, these findings suggest that clinicians should seek to identify and treat depressive symptoms as close to onset as possible, before harmful effects on stroke risk start to accumulate.”

The study examined 16,178 men and women who were over the age of 50 and were participating in the Health and Retirement Study between 1998 and 2010, where they were followed up with every two years. The participants were questioned about depressive tendencies, their history of stroke, and stroke risk factors. Out of the 16,178 participants, 1,192 had strokes during the study period, and the ones who did were more likely to have long-term depression.

It’s possible that depression and other mental illness may wreak havoc on the body’s cardiovascular system and vascular health. In addition, people with depression often find unhealthy ways of coping with it, such as drinking, smoking, or overeating.

However, the researchers plan on investigating the topic more in order to solidify their results.

“Because this is the first study to take this approach, we need replication of findings in independent samples, with people of different age groups, and exploring different reasons that depressive symptoms get better,” senior author Maria Glymour, an associate professor in the Department of Epidemiology and Biostatistics at the University of California, San Francisco, said in the press release. “The surprising results make such replications even more urgent.”

If you suffer from depression, find ways to lower your stress and anxiety by taking care of yourself, reaching out to a cognitive behavior therapist, eating well, and maintaining physical activity.

Source: Gilsanz P, Walter S, Tchetgen E, Patton K, Moon R, Capistrant B. Changes in Depressive Symptoms and Incidence of First Stroke Among Middle-Aged and Older US Adults. Journal of the American Heart Association. 2015.