Depression affects people's ability to smell, according to new research from Tel Aviv University.

"Our scientific findings suggest that women who are depressed are also losing their sense of smell, and may overcompensate by using more perfume," said Dr. Yehuda Shoenfeld. "We also believe that depression has biological roots and may be an immune system response to certain physiological cues."

Women who are depressed are also more likely to lose weight. With a reduced sense of smell, they are less likely to have a healthy appetite, he said.

Shoenfeld's research focuses on people who have both depression and lupus. He found that people with lupus or other immune system diseases develop a particle called an autoantibody that weakens the olfactory system and makes people feel depressed.

He said the results can be used for more than just lupus patients.

"People who are depressed seem to respond well to aromatherapy. Certain smells seem to help them overcome the effects of the biological factors, suggesting that depression may have a biological cause," he said.

Also, a smell test could be designed to test for depression.