20 Jul Co-morbid Insomnia and Obstructive Sleep Apnoea as a potential predictor of Suicide and Self-harm
Insomnia and obstructive sleep apnoea (OSA) are the two most common sleep disorders and frequently co-occur. Recent research is making an important contribution to knowledge of relationships between sleep disorders and mental health.
Co-morbid insomnia and sleep apnoea (COMISA) is a highly prevalent condition associated with worse morbidity compared to insomnia-alone or sleep apnoea-alone.
Up to 50% of people with OSA report co-occurring insomnia symptoms, including difficulties initiating sleep, maintaining sleep, and/or early morning awakenings from sleep, with associated daytime impairment.
People with worse sleep, and reduced COMISA also have increased depression prevalence and severity, quality of life, compared to people with OSA alone.
Studies have noted people with untreated OSA, insomnia symptoms were positively associated suicidal ideation after controlling for age and gender.
A recent study by Udholm et al reported on the association between diagnosed OSA and risk of suicide and self-harm in a Danish Nationwide cohort. Compared to age- and gender-matched people with no OSA diagnosis, people with a diagnosis of OSA had an increased risk of self-harm (composite variable), and death by suicide, over a mean follow-up of 12.5 years.
Continuous positive airway pressure (CPAP) therapy also moderates this association, with a trend for reduced risk of suicide, and a significant reduction in risk of self-harm among those people treated with CPAP, compared to those without CPAP.
Longitudinal associations between increasing severity of OSA and depression symptoms have also been reported in the Wisconsin Sleep Cohort study. Bishop et al investigated US Department of Veterans Affairs records and reported that sleep disorders (OSA, insomnia, and nightmares) are associated with increased suicide risk, and that treatment of sleep disorders may moderate this relationship.
The bidirectional association between insomnia and depression is well established in scientific literature.
Trials have also noted that CPAP therapy is associated with a reduction in depression symptoms in patients with OSA, with remission comparable to some antidepressants. The effect of CPAP therapy on reducing depression appears to be independent of reductions in daytime sleepiness, and is strongest among people with pre-existing depression.
This new research reflects the importance of linking and investigating large-scale data to identify risk factors for suicide, associations with sleep disorders, and potential avenues for early prevention.
There are several potential clinical characteristics and comorbidities of OSA that may contribute to the relationship between OSA, suicide risk, and self-harm.
Emerging evidence suggests that among people with COMISA, treating insomnia symptoms with CBTi improves insomnia symptoms and may increase subsequent acceptance and use of CPAP therapy. There is RCT evidence that both CBTi and CPAP therapy independently reduce depression severity.
The effect of combination CBTi and CPAP therapy on the reduction of suicide and suicidal ideation among people with COMISA is now a new area of research.
Research is also underway looking at identifying specific people at increased risk of suicide, and potential preventative measures and interventions.
There is an importance in measuring and linking data with various comorbid conditions (insomnia, pain, depression, cardiovascular disease), socio-demographic information, with management strategies eg non-CPAP therapies and antidepressants.
To assist identifying people with COMISA and to facilitate further investigation of COMISA data-linkage exercises some sleep clinics are using standardized measures of insomnia and circadian rhythm dysfunction with patient screening questionnaires.
Improving the identification in the features of OSA most closely linked to depression and suicidal ideation may be further improved by expanding the use of more detailed data from overnight sleep studies eg apnoea-induced sleep fragmentation, hypoxia, daytime sleepiness, cerebral gray matter structural changes, and metabolic abnormalities. All of these may be also reversed by CPAP therapy.
This research reflects the importance of good sleep for positive mental health, with further research in the area of sleep disorders, mental health, and suicide risk. This remains impacted by the high rate of undiagnosed OSA in the Australian population.
References
Obstructive sleep apnea and risk of suicide and self-harm: a Danish nationwide cohort study. Udholm N , et al. Sleep.2021;45(2).
Bi-directional relationships between co-morbid insomnia and sleep apnea (COMISA). Sleep Med Rev. Sweetman A , et al. 2021;60:1–14.
Suicidal ideation and insomnia symptoms in subjects with obstructive sleep apnea syndrome. Sleep Med. Choi SJ , et al. 2015;16(9):1146–1150.
Sleep, suicide behaviours, and the protective role of sleep medicine. Sleep Med. Bishop TM , et al. 2020;66:264–270.