Sleep-disordered breathing in major depressive disorder.

Individuals with major depressive disorder often experience obstructive sleep apnea. However, the relationship between depression and less severe sleep-disordered breathing is unclear. This study examined the rate of sleep-disordered breathing in depression after excluding those who had clinically significant sleep apnea (>5 apneas∙h⁻¹). Archival data collected between 1991 and 2005 were used to assess the prevalence of sleep-disordered breathing events in 60 (31 depressed; 29 healthy controls) unmedicated participants. Respiratory events were automatically detected using a program developed in-house measuring thermal nasal air-flow and chest pressure. Results show that even after excluding participants with clinically significant sleep-disordered breathing, individuals with depression continue to exhibit higher rates of sleep-disordered breathing compared with healthy controls (depressed group: apnea-hypopnea index mean = 0.524, SE = 0.105; healthy group: apnea-hypopnea index mean = 0.179, SE = 0.108). Exploratory analyses were also conducted to assess for rates of exclusion in depression studies due to sleep-disordered breathing. Study exclusion of sleep-disordered breathing was quantified based on self-report during telephone screening, and via first night polysomnography. Results from phone screening data reveal that individuals reporting depression were 5.86 times more likely to report a diagnosis of obstructive sleep apnea than presumptive control participants. Furthermore, all of the participants excluded for severe sleep-disordered breathing detected on the first night were participants with depression. These findings illustrate the importance of understanding the relationship between sleep-disordered breathing and depression, and suggest that screening and quantification of sleep-disordered breathing should be considered in depression research.