Sleep apnea is linked with an increased risk of depression in men, an Australian study found.
According to researchers from the University of Adelaide and the Adelaide Institute for Sleep Health, among 2,000 men ages 35 to 83 who were evaluated for depression, those with too much daytime sleepiness were 10% more likely to be depressed than those without. The connection held up even after taking other risk factors into account.
The study also found that clinical depression may speed up the aging process.
None of the men had been diagnosed with severe obstructive sleep apnea when they entered the study, however 857 of them were evaluated for the condition after joining. Those who were found to have the sleep disorder were 2.1 times more likely to be depressed than those who didn’t have it.
Some of the men had both acute sleep apnea and excessive daytime sleepiness. They found that there were 4.2 times more likely to be depressed compared with men who had no sleep issues. Those with both conditions were also 3.5 times more likely to be depressed than men with only one of them.
In order to give enough time for the researchers to see whether sleep problems could be linked to a recent diagnosis of depression, all participants in the study were evaluated for depression twice, with the second test taking place about five years after the first.
And indeed, the men who had severe sleep apnea that was discovered during the study were 2.9 times more likely to become depressed during those five years.
The study design did not allow researchers to verify whether sleep problems boosted the men’s risk of depression. It’s possible that the reverse is true, or that a third factor makes people more likely to be both depressed and to have trouble sleeping.
The study concluded that the results carry out actionable information for doctors, though the nature of the relation between sleep and depression is still unclear.
Patients should be screened for obstructive sleep apnea, even if they don’t seem to be sleepy, after diagnosed with depression.
The results were represented at the American Thoracic Society’s 2015 International Conference in Denver.