Stress doesn't cause multiple sclerosis, study suggests

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(CBS) Does psychological stress cause multiple sclerosis?

Stress has long been blamed for causing flare-ups of MS in patients already diagnosed with the incurable neurological disorder, but a new study suggests the link between stress and MS stops there.

"While we've known that stressful life events have been shown to increase the risk of MS episodes, we weren't certain whether these stressors could actually lead to developing the disease," study author Dr. Trond Riise, professor of lifestyle epidemiology at the University of Bergen in Norway, said in a written statement.

Riise and his colleagues looked at more than 230,000 women participating in the Nurses' Health Study, a vast research project launched in 1976. The women were asked about stress at home and work, in addition to physical or sexual abuse they suffered during childhood or adolescence. The authors identified 369 women with MS. But after controlling for age, ethnicity, weight, and other factors, they found that MS was not more common in women who reported stress or abuse.

"This rules out stress as a major risk factor for MS," Riise said.

But the study - published in the the May 31 issue of Neurology - has its critics.

"The main difficulty in studying stress specifically is, what does the word mean?" Dr. Thomas Mack, professor of preventive medicine and pathology at the University of Southern California, told Reuters Health. "Some people feel more stressed than others - whether there's any physiologic meaning to that is very difficult to know."

Almost 400,000 Americans suffer from multiple sclerosis. The disease attacks the central nervous system, causing symptoms that include fatigue, memory loss, and problems with balance and muscle coordination.

The National Institute of Neurological Disorders and Stroke has more on multiple sclerosis.