Add one more to the long list of downsides to financial stress—it makes you look older.

In a study published online in the journal Research on Aging, Brandeis professor of psychology Margie Lachman and several colleagues found that people with the highest levels of financial stress looked like they had aged more over a decade than people with lower levels of financial stress.

"It may be that people who are under a lot of financial stress do not pay much attention to their appearance," says Lachman. "Stress can also accelerate the aging process."

Lachman's co-author was Angela Lee Attardo at the Antioch University of New England. The first author of the paper was Stefan Agrigoroaei, a Belgian researcher at the Université catholique de Louvain.

Here's how the study worked:

Over two hundred people were asked to rate their level of financial stress. Headshots were taken of them in 1994-1995 and then again in 2004-2005. The photos were then shown to a separate group of 19 reviewers, who were asked to judge how old the people in the pictures looked.

The reviewers consistently estimated that those under financial stress had aged more than those who weren't under financial stress.

Lachman, the Minnie and Harold Fierman Professor of Psychology and colleagues, also studied how stress in general affects how old people think you are. They found that financial stress actually takes a larger toll on appearance than other types of stress. This is consistent with other research showing that money worries rate as the most significant source of stress in people's lives.

Finally, the research suggests that people are not the best judge of their appearance when it comes to aging. The individuals who had their headshots taken were asked how old they thought they looked to others. It turned out on average they thought they looked younger than the panel of reviewers.

Lachman, who is also the director of the Lifespan Developmental Psychology Lab at Brandeis University, is a leading expert on health and well-being in later life. While much research has focused on how old people feel, this study also looked at how old people appear to others relative to their actual age. Lachman says that being perceived as older than you actually are can affect behavior and lifestyle with the potential to negatively affect your health.