Scientists link depression to a biological mechanism that affects the olfactory glands

Jan 4 2008

Can't smell the roses? Maybe you're depressed. Smell too much like a rose yourself? Maybe you've got the same problem.

Scientists from Tel Aviv University recently linked depression to a biological mechanism that affects the olfactory glands. It might explain why some women, without realizing it, wear too much perfume.

Scientific research that supports this theory was published this year in the journal Arthritis and Rheumatism. “Our scientific findings suggest that women who are depressed are also losing their sense of smell, and may overcompensate by using more perfume,” explains researcher Prof. Yehuda Shoenfeld, a member of the Sackler Faculty of Medicine at Tel Aviv University. “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 says.

Prof. Shoenfeld draws his conclusions from lifetime research on autoimmune diseases, focusing on conditions such as lupus, arthritis and rheumatism.

Affecting about 1.5 million Americans, depression accompanying lupus, Prof. Shoenfeld has found, is much more than an emotional reaction to being ill. It appears to have a biological cause.

In lupus patients and those with other autoimmune diseases, a particle known as an “autoantibody” attacks the person's own immune system, appearing in the human body as an aberrant reaction to autoimmune diseases. This particle “is a real novelty,” says Prof. Shoenfeld. “We have found that, when generated, it weakens a person's sense of smell and can induce the feeling of depression.”

Scientists today widely accept the fact that people with Alzheimer's disease lose their sense of smell. Prof. Shoenfeld's research is the first that links depression to smell in lupus patients, however.

The implications are wide and can be applied to the general population, says Prof. Shoenfeld. “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.”

This research also raises questions about the cause of psychotic disorders such as schizophrenia. “There may be an organic cause to these disorders, and if this is the case, clinicians might have to change their attitude about current therapies they use,” Prof. Shoenfeld says. “I think that science is able to show that aromatherapy might not be just for quacks. After all, some of these remedies have been used since the time of the Egyptians to treat organic diseases.”

Prof. Shoenfeld also suggests that a standardized “smell test” could be used by doctors to help diagnose depression as well as autoimmune diseases.

He adds that the association between one's sense of smell and depression has interesting implications for “smell marketing,” used by retailers to encourage shoppers to buy, especially around holiday time. “These tactics are already being used by retailers and banks all over the world,” says Prof. Shoenfeld.

“The retail industry has learned that if it splashes good smells around, it can convince clients to buy more and invest more money. It certainly has an effect on one's mood.”

http://www.aftau.org/