When Lissa Schulz, a 34-year-old mother of two living in Austin, Tex., was diagnosed with depression six years ago, she never suspected that something that she was doing in her sleep could be the root of her problem.
"I used to feel depressed, tired all the time, and not feel rested even after 12-15 hours of sleep per night," Schulz said. "I felt frustrated, irritated, and felt like a zombie walking through life."
She twice tried taking antidepressants, but they did not help. And her fatigue began to rule her life.
"I used to close my eyes on a red light and tell my daughter to wake me up when the light turned green," she said.
But two years ago, Schulz began to see an end to her torment when she was diagnosed with obstructive sleep apnea (OSA) — a condition in which a person is unable to breathe properly while asleep.
In patients with OSA, the tissue in the back of the throat collapses during sleep and blocks the airway, which keeps the air from getting into the lungs. This situation leads to snoring, which is usually accompanied by periods of silence — pauses in breathing — followed by choking or gasping sounds when the airway reopens. This can happen several times during the night and can be extremely disruptive to sleep.
After struggling with treatments that did not work for her, Schulz tried treatment with Continuous Positive Airway Pressure (CPAP) — a breathing device that delivers continuous pressurized air into a person's airway as they sleep.
Today, a year and a half after starting CPAP, Schulz said she feels like a new woman. Schulz now needs only seven to eight hours of sleep each night, and is able to participate in three different school committees.
"I started singing to the radio a few days after starting treatment, something that I haven't done in years," she said. "And most of my symptoms disappeared six to 12 months after starting treatment."
In With the Good Air, Out With the Blues
A recent study published in the Journal of Clinical Sleep Medicine presents more evidence for Schulz's case. A study conducted by Dr. Daniel Schwartz at the University Community Hospital in Tampa, Fla., found that patients with Schulz's condition experienced less depression once they were treated with CPAP.
"Several patients referred to our sleep center, seemed to have some symptoms of depression or were already taking antidepressants," Schwartz said. "And these symptoms seemed to decrease after six weeks of treatment with CPAP."
The authors of the study also noted that this decrease in symptoms persisted even after a year of treatment.
"This study confirms findings of prior studies and addresses long term resolution of symptoms of depression after using CPAP," said Dr. Carmen Schroder, an instructor of psychiatry and behavioral science at Stanford University in Palo Alto, Calif.
What may be most surprising is the idea that many of these patients may not be depressed at all — just very, very tired.
"Fatigue and sleepiness can be caused by both depression and obstructive sleep apnea," says Dr. David Rapoport, medical director at New York University Sleep Disorders Center. "It can be hard to differentiate the underlying cause based on these symptoms."
Dr. Alan Pack, director of the Center for Sleep and Respiratory Neurobiology at University of Pennsylvania, agreed. "If a depressed patient has loud habitual snoring, we need to think about sleep apnea as well."
And the benefits of catching the condition early could extend far beyond a simple good night's sleep. On a long term basis, people with OSA are at a risk of developing stroke, high blood pressure, and heart disease. According to the American Academy of Sleep Medicine, 80 to 90 percent of adults with this disorder remain undiagnosed.
Depression and Snoring: Are They Related?
Depression and obstructive sleep apnea seem to co-exist in many patients, leading many experts to look for a link between the two conditions.
"The public should know about this association between depression and sleep apnea," Schroder said. "Seventeen to 20 percent of patients with depression who have underlying obstructive sleep apnea are currently undiagnosed."
There may even be a causal relationship between obstructive sleep apnea and depression.
"OSA seems to cause depression, but we can't exclude the possibility that depression may cause symptoms of OSA as well," Schroder noted.
But he added that the new research makes one thing clear. "Patients presenting with depression should also be screened for obstructive sleep apnea, especially if antidepressants don't seem to be helping."