It's the time of year when concerns about depression begin to crop up. Did you know that there have been some important findings about relationships between obstructive sleep apnea (OSA) and depression in the last few years?
Recent studies suggest that doctors may need to reconsider how they screen patients with depressive symptoms because these patients might also be struggling with undiagnosed OSA.
How are depression and OSA related?
It seems like a stretch to think that a condition as elusive as depression could lead to something as specific as OSA, or vice versa.
From the point of view of sleep clinicians, it's not uncommon to have patients with sleep issues, including OSA, who also suffer from depression. Both conditions share many of the same signs, even after taking variables like weight, age, gender or age into account: daytime fatigue, mood disorders, obesity, other preexisting health conditions, in example.
However, while sleep clinicians readily identify OSA and depressive disorders together in individual patients, practicing psychiatrists likely do not make the leap to OSA as a potential cause for depression in their patients because they are primarily looking only at emotional or behavioral symptoms.
Let's look at some basic statistics. If 25 million American adults suffer from OSA, and nearly 15 million American adults are affected by depressive conditions, it's not unreasonable to presume that there might be some crossover among these patient populations.
This is not to say that OSA causes depression or that depression causes OSA. But if we are to ensure proper diagnosis and treatment of either condition, perhaps the solution is to screen for both when a patient comes in with complaints that could be either/or.
What research tells us
Research in the past shows loose connections between OSA and depression. In a European study, Dr. Maurice Ohayon of Stanford found people with depression to be five times more likely to suffer from sleep-disordered breathing, with OSA as its most common presentation.
Results from the largest study in the US to closely examine a relationship between depression and OSA (SLEEP, April 2015) demonstrated that the actual breathing dysfunction that identifies OSA―the snorting, gasping and pauses in breathing―is also associated with nearly all depression symptoms.
The symptoms included "including feeling hopeless and feeling like a failure,” said the study's lead author, Anne G. Wheaton, PhD. She acknowledged that researchers expected subjects with OSA to struggle with sleeping and to report feeling tired all the time, but they didn't expect to uncover concerns more familiar to people with depression.
Then, last fall, an Australian study published in the Journal of Clinical Sleep Medicine showed evidence for two things: that doctors may be, in fact, underdiagnosing OSA patients by misdiagnosing them as depressed―when they could actually have both conditions; and that the use of continuous positive airway pressure (CPAP) therapy was exceptionally effective in treating patients with both problems.
CPAP: the missing link?
Dr. David R. Hillman, the study author, is a professor at the University of Western Australia and a sleep physician at the Sir Charles Gairdner Hospital in Perth. He established a team to look more closely at the two symptoms that most closely correlated to both OSA and depression: insomnia and fatigue. The goal was to determine whether OSA patients with depressive disorders might also benefit from using CPAP therapy for both conditions.
Not only did he discover that 70 percent of individuals with OSA also experience the symptoms of depression, but that their symptoms progressed on a scale that matched the severity of their sleep apnea.
But here's the good news: treating these study subjects with CPAP resulted in relief of clinically significant depressive symptoms for 96 percent of the patients who adhered to CPAP for three months. OSA symptoms improved as well.
Even better, of those who continued to use CPAP afterward, none who reported baseline feelings of self-harm―who expressed feeling they would be “better dead” at the beginning of the study―reported similar catastrophic thinking at the three-month follow-up.
“Effective treatment of obstructive sleep apnea resulted in substantial improvement in depressive symptoms, including suicidal ideation,” said Hillman.
Hillman also uncovered what may be perhaps a key reason why OSA so often goes unnoticed and undiagnosed. The findings in his study “highlight the potential for sleep apnea, a notoriously underdiagnosed condition, to be misdiagnosed as depression,” he said.
Making the most of patient screening tools
Clinicians are now discussing better screening practices for those incoming patients complaining of symptoms shared by both conditions.
People who struggle with depression may soon find a standard procedure in place that would also evaluate them for obesity, daytime somnolence, fatigue, a history of snoring, witnessed pauses in breathing, fragmented sleep and feeling tired all the time.
CPAP is an effective treatment and many support groups exist for users which can help them to get the most out of their therapy.
One important consideration: Some pharmaceutical treatments for depression, without taking unidentified OSA into account, can complicate matters. Patients with both OSA and depression must avoid certain medications commonly used to treat depression; their side effects may include further restriction of the respiratory system while sleeping, which could be dangerous for those with sleep apnea.
If you struggle with depression but are unsure whether you may also have sleep apnea, it makes good sense for you to consult your physician about any sleep symptoms you may also be experiencing.