Sleep apnea can affect your mood. After one night of poor sleep, you may notice yourself feeling irritable or unhappy. After many nights of poor sleep, this can really add up. But can sleep apnea cause full-blown depressive symptoms, beyond that general “blah” feeling? A recent study set out to examine the relationship between sleep apnea and depressive symptoms so that we may have a better understanding of how sleep apnea affects mood.
A research study, conducted by researchers in Seoul, Korea, included over 300 people with suspected sleep apnea. These were people who had come to the sleep lab with complaints of snoring, choking while sleeping, or excessive sleepiness. A commonly used depression scale (Beck Depression Scale) was completed by each of these participants prior to an overnight sleep study. In addition, each participant completed a sleep problems scale, which addresses how often they have sleep difficulties. Each subject underwent an overnight sleep study so that the research team could assess the presence and severity of sleep apnea, and statistical analyses examined whether or not those with worse sleep apnea had more depression symptoms.
It was found that, perhaps surprisingly, there was no direct link between sleep apnea and depression. In other words, although it was hypothesized that those with worse sleep apnea would have more depression symptoms, and vise versa, this result was not found. However, when taking into account the other questionnaires that were completed, it was found that there was a mediating factor present. A mediating factor is something that is necessary in order for two other factors to be related. In this case, the mediating factor was a sleep quality score, gauged using one of the questionnaires. Overall, it was found that sleep apnea was a predictor of higher depressive symptoms when the participants had poor self-rated sleep quality.
This is an interesting study, and it is very logical. It seems that sleep apnea and depression are linked but only when poor self-rated sleep is present. Perhaps this means that sleep apnea only really worsens sleep in some people, and these people are the ones who are most affected. An alternative possibility is that depression symptoms are dependent on how we think we slept. If an individual wakes up knowing they had a terrible night of sleep, they might be more likely to be moody and depressive than someone who believes their sleep is just fine. This is all speculation, of course, but everyone will benefit from treating sleep apnea. If there is no apnea, there is no worry about this analysis!
Lee, W., Lee, S. A., Chung, Y. S., & Kim, W. S. (2015). The Relation Between Apnea and Depressive Symptoms in Men with Severe Obstructive Sleep Apnea: Mediational Effects of Sleep Quality. Lung, 1-7.