Depression is a common disorder that exists along with obstructive sleep apnea (OSA). The exact relationship between the two disorders is not known. OSA may contribute to depression due to sleep loss, sleep disruption, and cognitive effects of intermittent low oxygen levels to the brain. Also, weight gain and sleep disruption from depression could exacerbate OSA. Some, but not all of my patients report that their depression gets better with treatment of OSA.
This study is a meta-analysis of research looking at the effects of CPAP and oral appliances on depressive symptoms (as obtained by depression questionnaires) in adults with OSA. The results showed small improvements in depressive symptoms with OSA treatment. The greatest benefit was seen in those patients with the worse depression scores at baseline.