Results from the study show that nearly 73 percent of sleep apnea patients — 213 of 293 patients — had clinically significant depressive symptoms at baseline, with no difference in symptoms between men and women. The more severe the sleep apnea, the worse the symptoms of depression, according to researchers.
But the study found that clinically significant depressive symptoms remained in only four percent of the sleep apnea patients who adhered to CPAP therapy for three months — just nine of 228 patients.
Of the 41 patients who reported baseline feelings of self-harm or that they would be “better dead,” none reported persisting suicidal thoughts at the three-month follow-up, researchers added.
“Effective treatment of obstructive sleep apnea resulted in substantial improvement in depressive symptoms, including suicidal ideation,” said senior author David R. Hillman, M.D., clinical professor at the University of Western Australia and a sleep physician at the Sir Charles Gairdner Hospital in Perth. “The findings highlight the potential for sleep apnea, a notoriously underdiagnosed condition, to be misdiagnosed as depression.”
The American Academy of Sleep Medicine reports that sleep apnea afflicts at least 25 million adults in the U.S. Untreated sleep apnea increases the risk of other chronic health problems, including heart disease, high blood pressure, Type II diabetes, stroke, and depression.
The study group was made up of 426 new patients referred to a hospital sleep center for evaluation of suspected sleep apnea, including 243 males and 183 females. Depressive symptoms were assessed using the validated Patient Health Questionnaire (PHQ-9), and the presence of obstructive sleep apnea was determined objectively using overnight, in-lab polysomnography.
Of the 293 patients who were diagnosed with sleep apnea and prescribed CPAP therapy, 228 adhered to the treatment, which was defined as using CPAP therapy for an average of five hours or more per night for three months.
According to the researchers, the results emphasize the importance of screening people with symptoms of depression for obstructive sleep apnea. These patients should be asked about common sleep apnea symptoms, including habitual snoring, witnessed breathing pauses, disrupted sleep, and excessive daytime sleepiness.
The study, supported by a grant from the National Health and Medical Research Council (NHMRC) of Australia, was published in the Journal of Clinical Sleep Medicine.