OSA and Depression: Is the Relationship Causal?

Obstructive sleep apnoea (OSA) and depression are two of societies highest priority public health issues. In Australia, approximately 5% of men suffer from depression (1) and up to 49% of middle aged men suffer from OSA (2). There is an alarmingly high association between the two disorders – in clinical studies 39% of those who suffer from OSA also suffer from depression (3).

Is this correlation directional or is there simply a symptom overlap? Excessive daytime sleepiness, lack of concentration, weight gain and loss of vigour are common to both OSA and depression. The research suggests that untreated OSA might be to blame.

A study of middle-aged Australian men with undiagnosed OSA found the odds of also having had depressive symptoms increased from 1.3 to 2 fold between mild-moderate and severe OSA, respectively (4). Another population-based study in Wisconsin, USA found that OSA is associated with increased depression in a severity related fashion (5).

The research suggests that OSA contributes to depression. How might this happen? There is extensive research to show that depression is associated with chronic, low grade inflammatory response by activation of cell-mediated immunity and increased oxidative and nitrosative stress. Repeated desaturation events experienced by undiagnosed OSA patients have been proposed to cause this chronic, low grade inflammatory environment leading to the progression of depression (6).

Where OSA goes undiagnosed in up to 82% of males (7), its recognition and diagnosis becomes even more important in the context of potentiating depression.

1. Bose, J., Hedden, S., Lipari, R., Park-Lee, E., Porter, J., & Pemberton, M. (2016). Key Substance Use and Mental Health Indicators in the United States: Results from the 2015 National Survey on Drug Use and Health. Rockville: SAMHSA.
2. Heinzer, R., Vat, S., Marques-Vidal, P., Marti-Soler, H., Andries, D., & Tobback, N. et al. (2015). Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study. The Lancet Respiratory Medicine, 3(4), 310-318.
3. McCall, W. V., Harding, D., & O’Donovan, C. (2006). Correlates of depressive symptoms in patients with obstructive sleep apnea. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 2(4), 424–426.
4. Lang, C. J., Appleton, S. L., Vakulin, A., McEvoy, R. D., Vincent, A. D., Wittert, G. A., Martin, S. A., Grant, J. F., Taylor, A. W., Antic, N., Catcheside, P. G., & Adams, R. J. (2017). Associations of Undiagnosed Obstructive Sleep Apnea and Excessive Daytime Sleepiness With Depression: An Australian Population Study. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, 13(4), 575–582.
5. Peppard, P. E., Szklo-Coxe, M., Hla, K. M., & Young, T. (2006). Longitudinal association of sleep-related breathing disorder and depression. Archives of internal medicine, 166(16), 1709–1715.
6. Berk, M., Williams, L. J., Jacka, F. N., O’Neil, A., Pasco, J. A., Moylan, S., Allen, N. B., Stuart, A. L., Hayley, A. C., Byrne, M. L., & Maes, M. (2013). So depression is an inflammatory disease, but where does the inflammation come from?. BMC medicine, 11, 200.
7. Young, T., Evans, L., Finn, L., & Palta, M. (1997). Estimation of the clinically diagnosed proportion of sleep apnea syndrome in middle-aged men and women. Sleep, 20(9), 705–706.