More than 70% of people with sleep apnea experience symptoms of depression, according to a new study published in the Journal of Clinical Sleep Medicine. Researchers say their findings indicate a possibility that the sleep condition could be misdiagnosed as depression.
However, the study also finds depressive symptoms among sleep apnea patients can be relieved with the use of continuous positive airway pressure (CPAP) therapy.
More than 25 million adults in the US have sleep apnea, or obstructive sleep apnea - a condition whereby breathing stops briefly and repeatedly during sleep. Chronic snoring is the most common sign of sleep apnea.
Previous studies have suggested sleep apnea can raise the risk for depression if left untreated, and the condition has been linked to increased risk for high blood pressure, heart disease, stroke and type 2 diabetes.
CPAP therapy is the most common treatment for sleep apnea. CPAP involves the placement of a mask over the nose and/or mouth during sleep, which helps keep the airway open by gently blowing air into it.
In this latest study, Dr. David R. Hillman, clinical professor at the University of Western Australia, and colleagues set out to gain a better understanding of the prevalence of depressive symptoms among individuals with sleep apnea, and to investigate whether CPAP may be effective for reducing these symptoms.
The greater the severity of sleep apnea, the higher the depression risk
The team enrolled 426 individuals - 243 men and 183 women - who had been referred to a hospital sleep center with suspected sleep apnea.
- Overweight, obesity, smoking, alcohol use or having a small upper airway are common causes of sleep apnea
- It is estimated that at least 2-3% of children in the US have sleep apnea
- Lifestyle changes such as losing weight, quitting smoking and avoiding alcohol can reduce severity of sleep apnea.
Using the Patient Health Questionnaire (PHQ-9), consenting participants were assessed for symptoms of depression.
Diagnosis and severity of sleep apnea were determined using overnight polysomnography, or a "sleep study," which records brain waves, blood oxygen levels, breathing, heart rate and eye and leg movements during sleep.
Sleep apnea was diagnosed in 293 participants, of whom 213 (73%) had symptoms of depression at study baseline. The greater the severity of sleep apnea, the higher the likelihood of depressive symptoms, the researchers found.
Participants who were diagnosed with sleep apnea were offered CPAP therapy 5 hours a night for 3 months. Treatment compliance was recorded, and the PHQ-9 was repeated after treatment ceased to determine participants' symptoms of depression.
The researchers found that the 228 participants with sleep apnea who adhered to CPAP therapy experienced a significant reduction in depressive symptoms after 3 months; once treatment ceased, only 9 (4%) of these participants had clinically significant symptoms of depression.
What is more, the team found that of the 41 participants with sleep apnea who reported feelings of self-harm or suicidal thoughts at study baseline, none reported any such feelings after 3 months of CPAP.
Dr. Hillman and colleagues say their findings highlight the importance of screening individuals with depression for signs of sleep apnea. Clinicians should ask such patients about disrupted sleep, breathing pauses, snoring, excessive daytime sleepiness and any other symptoms of sleep apnea, according to the team.
Dr. Hillman adds:
"The findings highlight the potential for sleep apnea, a notoriously underdiagnosed condition, to be misdiagnosed as depression."
Earlier this year, Medical News Today reported on a study published in Neurology that associated heavy snoring and sleep apnea with earlier decline in memory and thinking skills.