The findings remain true even when an individual doesn’t fit the usual profile of sleep apnea, which includes being a male with obesity who snores and struggles with daytime sleepiness.
“No one is talking about evaluating for obstructive sleep apnea as a potential cause of treatment-resistant depression, which occurs in about 50 percent of patients with major depressive disorder,” said Dr. W. Vaughn McCall, chair of the Department of Psychiatry and Health Behavior at the Medical College of Georgia at Augusta University.
Now he hopes they will.
The researchers found that obstructive sleep apnea occurred in 14 percent of 125 adult patients with major depressive disorder, insomnia and suicidal thoughts, even though the sleep-wrecking type of apnea was an exclusion criterion for the original study.
While more research is needed, McCall said the new findings already suggest that testing for obstructive sleep apnea should be part of the guidelines for managing treatment resistant depression.
“We were completely caught by surprise that people did not fit the picture of what obstructive sleep apnea is supposed to look like,” said McCall.
While it’s known that people with obstructive sleep apnea have higher rates of depression than other populations, little is known about rates of obstructive sleep apnea in patients with major depressive disorder. The team decided to look in a population of patients they already were studying.
The primary goal of the original study was to examine whether treating patients’ insomnia in addition to their depression reduced suicidal thoughts.
Patients who were considered at risk for obstructive sleep apnea were left out of the study since sleeping pills tend to relax muscles, and already too relaxed throat muscles are a primary problem in obstructive sleep apnea.
Also excluded were individuals with restless leg syndrome, which is common with sleep apnea even in patients on therapy, and those with morbid obesity, which is considered a major risk for obstructive sleep apnea.
But when the 125 people enrolled were actually tested with a sleep study at home or in a sleep center, the researchers still found the condition present in 17 of them.
The team notes that neither the degree of daytime sleepiness nor insomnia accurately predicted the severity of obstructive sleep apnea they identified in these patients and that six of the 17 individuals diagnosed were female, not obese and reporting insomnia rather than classic daytime sleepiness.
Treatment of obstructive sleep apnea may improve symptoms of depression, and comprehensive screening for the sleep problem should be included for treatment resistant depression, according to the investigators. These include researchers from the University of California, Irvine; the University of Wisconsin in Madison; Wake Forest School of Medicine in Winston-Salem, North Carolina; and the University of California, San Francisco.
“We know that patients with sleep apnea talk about depression symptoms,” McCall says. “We know that if you have obstructive sleep apnea, you are not going to respond well to an antidepressant. We know that if you have sleep apnea and get CPAP, it gets better and now we know that there are hidden cases of sleep apnea in people who are depressed and suicidal.”