Sleep apnea linked to depression

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Snorting, gasping, or short interruptions in breathing during sleep may be linked to depression symptoms, new research shows.

The more frequently people snort, gasp, or stop breathing for short periods of time while asleep, the more likely they are to have symptoms of depression, according to a government study of nearly 10,000 adults released today.

Snoring, however, was not linked to depression symptoms in the study, which appears in the April edition of the journal Sleep.

"Sleep is essential, and healthy sleep should be as important as healthy nutrition, physical activity, and smoking cessation in promoting overall health," the researchers write.

Sleep and Depression

"Sleep-disordered breathing" -- the snorts, gasps, and short pauses in breathing that characterize obstructive sleep apnea -- has been linked with depression in previous research.

But those studies typically were much smaller and focused on patients who had come into sleep labs and been diagnosed with sleep apnea, says Anne Wheaton, PhD, an epidemiologist at the CDC's National Center for Chronic Disease Prevention and Health Promotion.

Wheaton’s study is the first to look at the connection between sleep-disordered breathing and depression in a nationally representative sample of U.S. adults. They took part in the National Health and Nutrition Examination Survey, or NHANES, from 2005 to 2008.

For NHANES, people reported how frequently they snored and snorted, gasped, or briefly stopped breathing while asleep. They also completed a short questionnaire about depression symptoms and had their height and weight measured.

The results:

• Six percent of men and 3% of women said a doctor had diagnosed them with obstructive sleep apnea.

• Seven percent of men and 4% of women said they snorted/stopped breathing at least five nights a week.

• Men and women who said they snorted/stopped breathing at least five nights per week were three times more likely to show signs of major depression, compared to those who said they never snorted or stopped breathing during sleep. That takes into consideration other factors, such as weight, age, sex, and race.

Possible explanations for the link between sleep-disordered breathing and depression include diminished oxygen to the brain and interrupted sleep, Wheaton says.

More research is needed to determine whether treating apnea patients for depression would improve their quality of life and whether treating depressed patients for sleep-disordered breathing would reduce their need for antidepressants, Wheaton says.

“Many sleep specialists do routinely screen for depression,” says sleep specialist Amy Aronsky, DO, medical director of a sleep facility in Longview, Wash. Depression might result from untreated sleep disorders, Aronsky says, and poor-quality sleep might worsen depression symptoms.

Which Comes First?

A key question is whether sleep apnea actually causes depression. The new study doesn't settle that.

Answering that question would mean following people for years, an expensive proposition, notes Paul Macey, PhD, assistant professor in-residence at the UCLA School of Nursing and Brain Research Institute. Macey was not involved with Wheaton’s study. Last year, he says, he began asking patients to draw up a timeline of their symptoms. He expected sleep apnea would come first, followed by the depression.

“That hasn’t been the case,” Macey says, cautioning that the evidence “is still anecdotal at this point.”

SOURCES:Wheaton, A. Sleep, April 2012.Anne Wheaton, PhD, National Center for Chronic Disease Prevention and Health Promotion, CDC.Paul Macey, PhD, assistant professor, UCLA School of Nursing and Brain Research Institute, Los Angeles, Calif.Amy Aronsky, DO, sleep specialist, Longview, Wash.