"The whole having MS s is depressing because it's a loss," said Mazur. "It can cause loss of many functions."
Half of MS patients suffer from depression. UCLA neurologist Dr. Nancy Sicotte's initial goal was to find out how MS affects a specific region of the brain's hippocampus.
All her MS patients had shrinkage in CA1 subregion. Then she and her colleagues found something unexpected. Every MS patient who was depressed also had a change in this area next door.
"We found these changes related to depression and high cortisol in a separate area," said Sicotte.
Sicotte says changes in the CA23 area appears to be a physical sign of depression.
Depressed study participants also had abnormally high levels of the stress hormone cortisol.
"They are not showing the normal decrease and by the end of the day they are still higher," said Sicotte.
Researchers have known that people with depression have high levels of cortisol. But is it the cortisol causing the physical changes, or vice versa?
Sicotte thinks it's a vicious cycle, and if people can find a way to interrupt the cycle then they can begin to feel better.
"If you could decrease the cortisol or improve the mood in other ways, for example anti-depressants reverse this change that we are seeing," said Sicotte.
Sicotte says studying this change in the brain could someday lead to new ways to address depression or at least help doctors chart a patient's progress.
Alyssa Mazur says just knowing depression is something physically real and tangible already lifts her spirits.
"I feel that it will ease some people's minds," said Mazur. "There is a way to possible modify it. Or shed some light on it."